“A useful summary of the test for whether there has been a material change in circumstances was set forth in the case of Poulter v. Poulter, 2005 BCCA 227 (B.C.C.A.) at para. 11 as follows:
The changes must be such that they were not known to the parties or to the judge at the time when the first final support order was made. Second, they must be such that they could not reasonably have been in contemplation of the parties or the judge. The third is that if they had been known, a different order would have been made than the one that was actually made. And fourth, that the different order would have been different in respect of the weight and consequences of the change and would have taken into account the change to make an alteration in the result.
In the case of Boston v. Boston, 2001 SCC 43 (S.C.C.) Major, J., writing for the majority, noted at para. 61 that on retirement, the pension-holding spouse may apply to vary a support order if his ability to pay support is compromised, and that the decision of whether to vary support depends on whether the applicant can demonstrate that there has been a material change in circumstances.
A material change of circumstances will vary from one case to another, particularly in relation to foreseeability. Retirement from employment can be a change of circumstances even if it is clearly foreseeable: Stones v. Stones: 2004 BCCA 99, at para. 15. (See also Schulstad v. Schulstad, 2017 ONCA 95 (C.A.) at para. 31 and Arthur v Arthur, 2018 ONSC 6682 (S.C.J.) at para. 42)”