ERICKSTAD, Chief Justice.

Timothy Winn appeals from a judgment of the district court changing custody of his two children, Ryan and Sarah Winn, to their mother, Shawna Delzer, formerly Shawna Winn. We reverse.

Shawna and Timothy were married in Beulah, North Dakota, on August 11, 1984. They had two children during their marriage, Ryan and Sarah. They were divorced on January 15, 1990. Following a contested custody hearing, Timothy was awarded custody of the two children, who were of the ages of four years and one and one-half years at that time. Timothy maintained custody of Ryan and Sarah until March 1, 1992, when the district court ordered Timothy to relinquish custody of the two children to Shawna.

During the modification hearing, Shawna conceded that she had experienced personal problems at the time of the original award of custody. She said that at that point in her life she was immature, angry, misguided, and lacked direction. Subsequent to her divorce she moved to Eureka, South Dakota, married Rick Delzer whom she met in church in Bismarck while separated, but not divorced, from Timothy, bought a house with Delzer, and was in the process of completing her nursing degree. Upon receiving her degree, she will be employed by a nursing home in Eureka, three blocks from her home. Her life, according to Shawna, had taken a considerable turn for the better, apparently, now that she was living with a less domineering and more loving person.

This change was instrumental in prompting Shawna to petition the district court for a modification in custody. Shawna asserted that she would be better able to provide a fitting home for her two children than Timothy. She pointed out that she would not be working as many hours as Timothy, so she would have more time to devote to Ryan and Sarah. However, the children would still have to be cared for by someone else during Shawna's eight hour shifts at the nursing home. Shawna showed intense concern over the fact that Ryan and Sarah were taken to Timothy's sister's home for care during the nine or ten hours he was at work. Shawna contended that it was Timothy's sister who was raising the children, not Timothy. Additionally, Shawna urged the district court that she would provide the children with better educational instruction, religious training and medical care.

Shawna contended that Timothy had not discerned that Sarah had ringworm, which Shawna discovered while bathing Sarah. When treated with Tinactin, the ringworm disappeared, only to reoccur on Sarah's temple and be successfully treated on a weekend with Shawna. Shawna also contended that Sarah, on one visit, had not bathed for three days because she refused to take a bath. This, Shawna contended, was because Sarah's feet, which Shawna discovered were blistered, hurt Sarah. After an examination by Dr. Susan Ostrowski of Eureka, and after receiving about four different prescriptions for a fungus, plus an antibiotic, the condition was apparently alleviated. It became necessary also to purchase canvas shoes in lieu of plastic shoes and take other precautionary measures to prevent a reoccurrence. Shawna also found it necessary to take Sarah to the doctor because of a bronchial infection, and she apparently monitored Ryan for his allergies.

Shawna's testimony reflected that her concern went beyond the children's physical health; she was troubled about their mental, emotional and educational well-being as well. Shawna asserted that Ryan might now be dominating Sarah as Timothy had allegedly dominated her during their marriage. Shawna, to aid Ryan in his studies, worked with him on connecting lines in a book of mazes.

All these and other things that Shawna has done for the children are laudable, but hardly something unusual for a loving parent. Further, these actions are what she could continue to do as a non-custodial parent with weekend visitation privileges.

Despite the changes in Shawna's life, very little changed in the custodial parent's life from the time of the divorce to the modification hearing. Timothy remained employed at the coal-gasification plant in Beulah. At the time of the hearing, his sister cared for the children while he was at work, just as she had always done. He had not remarried. He frequently took the children to see both pairs of grandparents, who lived in close proximity to the children and Timothy. Although not a perfect father, he tended to his children's emotional, physical and mental needs to the best of his ability. Ryan and Sarah appeared to be progressing and developing at a normal rate for children their age, and seemed to be happy with their father.

Upon consideration of the evidence, the district court found that the change in Shawna's life equated a significant change in circumstances.

"The court finds changed circumstances here.

". . . . She is now stable, mature, responsible and employed. The absence of those attributes two years ago at the time of the divorce had great effect on the court in granting custody to the father. Her changed circumstances have resulted in a more balanced or level field between the parents. Where before the court had doubts as to the mother's capacity to care for the children as a custodial parent, those doubts are now resolved favorably to her."

Furthermore, the court went on to find that the best interests of the children would be met by allowing the children to reside with Shawna.

"The court finds more growth potential for the children with the mother than has been demonstrated by the father these past two years. Rearing and nurturing are more than bathing, feeding and clothing. He has performed the latter functions adequately. However, the court finds the mother can excel in the former. The court has been markedly impressed by the mother's efforts, in spite of the distance, to remain intimately involved in and providing the nurturing of these children. A strong emotional bond exists."

Based on these findings, the district court changed custody from Timothy to Shawna, allowing Shawna's previous visitation schedule to become Timothy's. Timothy appeals this decision to our Court. For the reasons that follow, we reverse the district court's judgment, and order that custody of Ryan and Sarah be returned to their father, Timothy.

A court's analysis in considering a motion to modify custody should be different from that used when awarding original custody. Orke v. Olson, 411 N.W.2d 97, 99 (N.D. 1987); Miller v. Miller, 305 N.W.2d 666, 671 (N.D. 1981). The single issue determined during the original award of custody is the child's best interests. Section 14-09-06.1, N.D.C.C. See also Starke v. Starke, 458 N.W.2d 758, 760 (N.D.App. 1990); Orke, 411 N.W.2d at 99; Koller v. Koller, 377 N.W.2d 130 (N.D. 1985); Ebertz v. Ebertz, 338 N.W.2d 651, 654 (N.D. 1983); Miller, 305 N.W.2d at 671. However, when a motion for modification is before a trial court, it must consider two things:

"First, the trial court must determine whether or not there has been a significant change in circumstances subsequent to the original divorce decree and custody award. Heinen [ v. Heinen], 452 N.W.2d [331] at 333; Anderson v. Anderson, 448 N.W.2d 181, 182 (N.D. 1989). Second, the trial court must determine whether or not the changes which have occurred are such that it would be in the best interests of the child to modify the original custody award. Heinen, 452 N.W.2d at 333; Anderson, 448 N.W.2d at 182."

Reede v. Steen, 461 N.W.2d 438, 440 (N.D. 1990). See also Orke, 411 N.W.2d at 99; Koller, 377 N.W.2d at 130; Ebertz, 338 N.W.2d at 654; Miller, 305 N.W.2d at 671, Silseth v. Levang, 214 N.W.2d 361, 364 (N.D. 1974).

The burden of proving the substantial change, and usually its accompanying detrimental effect on the child's best interests, falls on the party seeking the modification of custody. This principle is deeply entrenched in child custody cases.

"The party seeking the modification of the custody award has the burden of showing the existence of a change of circumstances which requires a change in custody. Heinen, 452 N.W.2d at 333; Pitsenbarger v. Pitsenbarger, 382 N.W.2d 662, 664 (N.D. 1986)."

Reede, 461 N.W.2d at 440. Thus, in the present case, Shawna has the burden of proving a significant change of circumstances requiring a change of custody.

Here, Shawna contends that the changes in her life are so good that she should now, after the passage of over two years, be given custody. That is not the usual basis for gaining a change in custody. Notwithstanding that fact we must apply the usual standard of review.

"The application of the `clearly erroneous' standard of review to child custody cases is well-settled. Bader v. Bader, 448 N.W.2d 187, 188 (N.D. 1989); Lapp v. Lapp, 293 N.W.2d 121, 124 (N.D. 1980). In Lapp we stated that `[a] trial court's determinations on matters of child custody, child support, alimony, and the division of property are treated as findings of fact. The findings of the trial court will not be set aside on appeal unless they are clearly erroneous.' [Citations omitted.] Lapp, 293 N.W.2d at 124-25."

Reede, 461 N.W.2d at 440.

This Court will not reverse the trial court on its findings of fact unless those findings are clearly erroneous pursuant to Rule 52(a), N.D.R.Civ.P. To find a Rule 52(a) error, we must be "left with a definite and firm conviction that a mistake has been made." Miller, 305 N.W.2d at 671. See also Gross v. Gross, 287 N.W.2d 457, 459-60 (N.D. 1979).

Significantly, in a very recent case, we noted that "[t]here is an `aversion' to changing the custody of a happy child who has been living with one parent for a substantial time." Blotske v. Leidholm, 487 N.W.2d 607, 612 (N.D. 1992) (Erickstad, C.J., and VandeWalle, J., specially concurring). Maintaining stability and continuity in the child's life is a very compelling consideration when determining child custody issues. This is especially true when modification of custody is sought. "In a modification proceeding, the best interests of the child must be gauged against the backdrop of the stability of the child's relationship with the custodial parent." Blotske, 487 N.W.2d at 610.

In the case on appeal, prior to the modification of custody, Ryan and Sarah lived with their father for approximately two years. They had a stable environment. The record reflects that they were accustomed to the routine of their lives with Timothy. This continuity should not simply be discarded or interrupted merely because their mother has now improved her life and may be able to give them moderately better surroundings.

When considering a modification of custody, a substantial change of circumstances is not enough to warrant a change in custody. In addition, "[t]he significant change in circumstances must so adversely affect the child that custody should be changed." Blotske, 487 N.W.2d at 609 (emphasis added). See also Gould v. Miller 488 N.W.2d 42 (N.D. 1992).

We have said:

"Consecutive determinations about custody cannot change custody back and forth as the scales settle slightly toward first one parent and then the other as their circumstances change. The concept cannot be so erratic. `We have recognized that it is not in the best interests of a child to unnecessarily change custody and bandy the child back and forth between the parents.' Lapp v. Lapp, 293 N.W.2d 121, 128 (N.D. 1980). Before a change of custody can be deemed necessary for the best interests of the child, there must be some consideration of the effect of the change on the child. See Silseth v. Levang, 214 N.W.2d 361 (N.D. 1974) and Jordana v. Corley, 220 N.W.2d 515 (N.D. 1974)."

Orke, 411 N.W.2d at 100.

This is not the first time we have faced a situation where the non-custodial parent has rehabilitated his or her life and sought modification of custody based, at least partially, on those improved personal circumstances. In the past, we have not been persuaded that this alone is sufficient to upset the continuity and stability of the child's life. We normally insist that the change in circumstances weigh against the best interests of the child before we will approve a change in custody.

The most recent case involving facts similar to the above is Blotske, 487 N.W.2d 607. The custodial parent in Blotske was the mother. The father moved for a modification in custody, citing his improved personal circumstances as justification for a change in custody. The district court modified custody in favor of the father, and we reversed. The district court was convinced that the father had a greater capacity and disposition for giving love, affection and guidance to the child. Yet, it also found that the child was normal, did well in school, and loved her mother. In reversing the district court, Justice Levine, speaking for this Court, said:

"[w]hile [the father's] love and disposition for affection may exceed [the mother's], nonetheless, according to the trial court, `[n]othing in the evidence suggests that [the mother] lacks the ability to fulfill her parental role'; that `[the mother] is presently providing' [the child] with `food, clothing, medical care, and other material needs' and `that there is no substantial evidence that [the mother] is not presently carrying out her parental responsibilities in an appropriate manner.'

If this were an original custody proceeding, the finding in favor of [the father] would be well within the trial court's prerogative. But this is a change of custody proceeding. Accordingly, we are left with a definite and firm conviction that the trial court made a mistake."

Blotske, 487 N.W.2d at 611.

The facts in the present case are very similar to those in Blotske. Shawna, in her new life, was found by the district court to exceed Timothy in her disposition and potential to nurture and educate the children. However, the court did not find Timothy incapable or unable to perform his parental functions adequately. In ordering the change in custody, the district court found that the positive changes in Shawna's life "resulted in a more balanced or level field between the parents." Timothy had not experienced negative changes in his ability to parent since the time of the original custody award, nor did the changes which occurred in Shawna's life weigh against the best interests of the children. The change was that Shawna's life had improved. This did not change the stable relationship between the custodial parent, Timothy, and the children, nor should it.

In Orke, 411 N.W.2d 97, where the father had improved his own life circumstances, we pointed out that the non-custodial parent's redemption was not sufficient to change custody and disrupt the stable relationship between the child and the custodial parent. Further, we said that just because the child might have a better life with the recently reformed non-custodial parent, the issue was not resolved by that determination alone.

"[The father's] redemption as a parent may be a significant change of circumstances, but that only begins the inquiry, and the conclusion that `it would be better for [the child] to be with the other family' does not satisfactorily complete the inquiry. Miller v. Miller, supra.. . .

"Thus, in Miller v. Miller, supra, we pointed out that `[t]he change of circumstances must weigh against the child's best interests before a change in custody is justified.' 305 N.W.2d at 672."

Orke, 411 N.W.2d at 100 (emphasis added). See also Starke, 458 N.W.2d at 761 ("[a]lthough the evidence may show a marginal improvement in the children's life because of [the father's] improved family life and stability, we believe the trial court's decision to change custody failed to recognize the continuous and uninterrupted relationship that has been important to the children since the divorce").

Perhaps the case most similar in facts to the instant case is that of Ludwig v. Burchill, 481 N.W.2d 464 (N.D. 1992). In Ludwig, custody was awarded to the father following the divorce. The child, as in this case, lived with his father for approximately two years prior to the modification hearing. The child was exposed to his extended family quite frequently, including extensive contact with his father's sister, just as in this case. The mother did not have extended family to offer the children, much like Shawna's situation. The district court noted that the father was not a perfect father, and that the mother's circumstances had improved since the time of the original custody award. However, it refused to modify custody, citing the importance of maintaining continuity for the child. We agreed with the district court that the change in circumstances did not require a change of custody, and that nothing weighed against the child's interests by maintaining the current custody arrangement. Id. at 469. See also Silseth, 214 N.W.2d at 364 (although mother had improved her life circumstances, a change of custody from father to mother was not warranted because father was not an unfit parent, and also, the best interests of the child did not require a change in custody).

It is true that in Von Bank v. Von Bank, 443 N.W.2d 618 (N.D. 1989), this Court affirmed a change in custody based on a change of circumstances weighing against the best interest of the child. We believe that case is distinguishable on its facts. In Von Bank, the child suffered many health problems, somewhat similar to the present case. However, the mother, the custodial parent, had knowledge of the illnesses and would not seek treatment for the child until the child was in severe pain. Here, once Timothy became aware of any illnesses his children had, he appeared to attend to the situation adequately.

Also in Von Bank, the child was exposed to events in her home life that Timothy's children did not experience. For instance, in Von Bank, the mother and child shared the same bedroom in which they each had their own bed. Yet, the mother would allow her fiancé to sleep in bed with her while the child slept in her own bed.

Furthermore, the custodial parent in Von Bank attempted to frustrate the non-custodial parent's visitation. In fact, the trial court found that the custodial parent was attempting to frustrate the entire child/parent relationship between the child and the father. Additionally, the mother's fiancé insisted he did not want the father to come to the fiancé's farm to pick up the child for visitation. In the present facts, Timothy appears to have been very cooperative and open to Shawna's visitation. She was able to exercise her visitation liberally.

Also, unlike Timothy, the custodial parent in Von Bank was making substantial changes in her life. The trial court did not view the changes positively. She was engaged to be married. After the marriage she intended to move her and the child onto her husband's farm. The trial court did not look favorably on the child moving to an isolated rural Minnesota area, given the child's emotional and mental state.

Most importantly, while in the custodial parent's care, the child in Von Bank was evaluated as showing signs of depression and social isolation. Quite the contrary is true in the present case. Both Ryan and Sarah were assessed as being normal, healthy children with no significant or major problems.

Both the district court and Shawna believe that changing custody would improve the children's lives. Shawna has redeemed herself and is now ready, willing and able to step in and take custody of her two children. In our view, Shawna and the district court have failed to give sufficient importance to the fact that Timothy has apparently been doing reasonably well in raising these two children for over two years. He is not deficient in his parenting. He is not unfit. The improved circumstances in Shawna's life do not lessen the good relationship Timothy has with Ryan and Sarah. That relationship has remained constant. The changed circumstances may enhance Shawna's relationship with the children, but that alone does not justify a change in custody.

If the district court had found evidence that the relationship between Timothy and his children was negatively affecting the best interests of the children, then the change in custody might have been required. That was the situation in Ebertz, 338 N.W.2d 651. There we found that the mother's improved financial and marital status equated a significant change of circumstances. However, that alone was not enough to change custody in her favor. Additionally, in Ebertz we placed significant importance on the fact that the children's "cognitive, perceptive, and motor skills [were] below the expected levels" due to "`a lack of usual stimulation' available to children" while in their father's custody. Id. at 653-654. These facts weighed against the children's best interests, requiring a change in custody. Id. at 654.

There are no such facts in the present case. Nothing in the record illustrates to this Court that maintaining custody with the father, while the mother has liberal visitation privileges which she exercises, apparently without resistance, would weigh against the best interests of the children. Although it is arguable that the children might experience marginal improvements in their lives if custody were given to their mother, this alone does not justify "bandying" these two children back and forth between the parents. The memorandum findings are too anemic and the record too lacking in substantive specifics to justify the change in custody from one parent to another. See Blotske v. Leidholm, 487 N.W.2d 607.

For the foregoing reasons, partly because we believe the district court had an erroneous view of the law and partly because we are convinced a mistake was made in determining the pertinent facts and applying them to the law which is crucial when determining whether or not a change in custody should be made, we reverse the judgment of the district court and return custody of Ryan and Sarah to Timothy, with visitation privileges to Shawna on the basis of the judgment previously existing.

VANDE WALLE, J., concurs.