Nathan P. Dressel, Relator, vs. Spee-Dee Delivery, Service, Inc., Respondent, Commissioner of Economic Security, Respondent.

may not be cited except as provided by

Minn. Stat. § 480 A. 08, subd. 3 (1998).

 STATE OF MINNESOTA

 IN COURT OF APPEALS

 C3-98-2117

In Re the Marriage of:

Mark Jeffrey Enzler, petitioner,

Respondent,

vs.

Ellen Christine Enzler,

Appellant.

 Filed April 27, 1999

 Affirmed

 Amundson, Judge

Olmsted County District Court

File No. F0951854

Lawrence D. Downing, Lawrence Downing & Associates, 330 Norwest Center, 21 First Street Southwest, Rochester, MN 55902 (for respondent)

Roger E. Petersen, Peterson & Mulcahey, 119 Sixth Street Southwest, Suite B, Rochester, MN 55902 (for appellant)

Considered and decided by Anderson, Presiding Judge, Crippen, Judge, and Amundson, Judge.

 U N P U B L I S H E D O P I N I O N

 AMUNDSON, Judge

Appellant Ellen Enzler challenges the district court's denial of her motion to modify respondent Mark Enzler's spousal maintenance obligation. Appellant contends that her inability to attain the educational goals contemplated in the dissolution decree is attributable to her son's worsening cerebral palsy and that her temporary maintenance award should be made permanent. We affirm.

 FACTS

The parties were married in 1988. During their marriage, they had one child, R.C.E., now eight years old. T.T.E., now fifteen years old, was appellant's child from a previous marriage and was adopted by respondent. T.T.E. has cerebral palsy. The parties separated in 1992 and again in October 1994. The dissolution judgment and decree were entered on March 22, 1996.

The decree states in part that

[t]he Husband shall pay to the Wife for her maintenance the sum of $1,200.00 per month commencing on February 1, 1996 and continuing on the 1st day of each and every month thereafter until June 30, 1998.

In May 1998, as her temporary maintenance award was to expire, appellant brought a motion to modify her maintenance to make it permanent, or at least to continue it until T.T.E. reached age 18. In the affidavit accompanying the motion, appellant stated that she would not receive her four-year nursing degree until June 1999 and that her son's cerebral palsy had worsened, making it difficult to attain her education and employment goals. She provided a list of 41 medical and dental appointments and emergency room visits that her son had required during 1997.

The district court denied appellant's motion and this appeal followed.

 D E C I S I O N

 I. Modification

We review a district court's determination of modification of spousal maintenance for an abuse of discretion. Stich v. Stich, 435 N.W.2d 52, 53 (Minn. 1989). A district court abuses its discretion only if its conclusions are "clearly erroneous[,] * * * against logic and the facts on record." Rutten v. Rutten, 347 N.W.2d 47, 50 (Minn. 1984). The district court's findings with regard to maintenance are also upheld unless "clearly erroneous." Gessner v. Gessner, 487 N.W.2d 921, 923 (Minn. App. 1992).

Minnesota law requires the district court to consider two things before modifying a maintenance award: (1) whether there has been a significant change in the parties' circumstances, and (2) whether this change has rendered the terms of the original decree unreasonable and unfair. Minn. Stat. § 518.64, subd. 2 (1998); Videen v. Peters, 438 N.W.2d 721, 724 (Minn. App. 1989), review denied (Minn. June 21, 1989). A substantial change in circumstances may be shown by: (1) a substantial increase or decrease in the earnings of a party, (2) a substantial increase or decrease in the need of a party, (3) a receipt of assistance, or (4) a change in the cost of living of either party. Minn. Stat. § 518.64, subd. 2 (a).

Appellant argues that her maintenance award should be extended at least until her son T.T.E. reaches age 18 because his cerebral palsy has worsened, appellant has been unable to reach her educational goals because of his condition, and because at age 46 and with outdated employment skills, it is difficult for appellant to find work that pays well. The district court, relying on Hecker v. Hecker, 568 N.W.2d 705 (Minn. 1997), first made a finding that appellant's failure to rehabilitate was a substantial change in circumstances, but ultimately concluded that the change did not make the original award unreasonable or unfair because the change was based on the wife's willful failure to rehabilitate. Then, relying on Hecker, the district court imputed income of $30 per hour over a twenty-hour workweek to appellant.

The district court apparently based its finding of willful failure to rehabilitate on the slow progress that appellant was making toward attaining her nursing degree and her failure to seek work that pays well. The district court conceded that T.T.E. "has required additional surgeries and medical care." But the district court apparently determined that this was offset by the money for housing, appellant's education, and medical expenses that respondent has paid above what the judgment and decree required. The district court also acknowledged that respondent's income had substantially increased since the time of the judgment and decree.

Whether a party acts in good faith is essentially a credibility determination, to which this court should defer. Tonka Tours, Inc. v. Chadima, 372 N.W.2d 723, 728 (Minn. 1985); see Sefkow v. Sefkow, 427 N.W.2d 203, 210 (Minn. 1988) (appellate courts defer to district court credibility determinations). Accordingly, although the question of whether appellant's failure to rehabilitate was willful is a close one, we defer to the district court's finding on this issue. Likewise, although it may seem unrealistic to impute income of $30 per hour to a woman of appellant's age, work experience, and education, we do not find that the district court abused its discretion in setting imputed income at this level, especially because a considerably lower hourly wage would also enable appellant to meet her reasonable monthly needs.

 II. Attorney Fees

Appellant also contends that the district court abused its discretion in denying her attorney fees. Minnesota law provides for attorney fees for proceedings under chapter 518. Minn. Stat. § 518.14, subd. 1 (1998). Fees are available if the court finds: (1) that the fees are necessary to the assertion of a party's rights and that they will not contribute unnecessarily to the length and expense of the proceedings; (2) that the party being asked to pay has the means to pay; and (3) that the party asking for the fees does not have the means to pay. The court may also award additional fees against a party who "unreasonably contributes to the length or expense of the proceeding." Id.

Again, we do not find that the district court abused its broad discretion in failing to award attorney fees to appellant.

  Affirmed.