I see where you are going with this

All I did was set myself a calendar reminder for 89 days to the hours (so 24hrs left) then another one when 12hrs left, then another one when 6hrs left, one for 3hrs left anf finally one for 1hr left. This way no matter what time of day it is I get a reminder, so if I am at work and won't be able to do with when the full 90 days runs out, I have a reminder to do it before I leave or whatever...