I’d like to pace this like an Anime series:
1-4, 1-6 (depending on how fast our pace gets): Monster of the week, character development
4-12, 6-12: Resolution of whatever conflict arises at the end of the MotW phase. Either the PCs win (and necessitate the reveal of a bigger bad/more severe threat/nice job breaking it hero) or they lose (And it’s Heroic BSOD/Big No time)
13: Review session, planning for the 2nd half of the series.
14-16: Character development
16-22: Things go to hell
23-24: Setup for the end
25-26: Epic conclusion
If PC’s issues are going to be resolved/future aspects taken, they’ll probably reach that point either at midseason or at the very end. Or some of each.