I have several pills that I take at different times throughout the day. I'm actually pretty good at remembering that at 9:00 it's time to take Medication X, etc. But sometimes 9:00 comes, I think to myself "Ok, it's time to take Medication X," I reach over to grab the bottle, but then some other random thought pops into my head (like if the TV is on in the background and something catches my attention for a beat)...and then one minute later I'll be like "Wait, did I actually take Medication X?" I'll have a memory of having the initial thought and of reaching for the bottle, but then I can't remember whether I actually took the pill or whether the random thought distracted me and I never completed the action.
I know pill organizers would largely solve this problem, I'm mostly just here to vent about the fact that I'm not even 40 and sometimes I feel like I'm 80.