I have gone thru every calendar on the Play Store, and there is only one that works everytime, all the time.
Google Calendar.... when I installed and started using that one, I never missed another appointment, nor an alarm at a weird date/time no matter how far in advance I set it.
Just last Thursday, the doctor set our next visit for 4 months down the road, Dec 13th at 2:30 PM
Google Calendar took it w/o any complaint....
and it has never failed to alert me.... good thing too, that Dr. appointment last Thursday?
We had forgotten to mark it on our paper calendar, the one that is stuck to the fridge with magnets
Beep! Beep! hey guys, time to go see the doc... wife was very surprised, as she has to have her labs done a week before.... and I had set it for a 7 day preAlert just for that purpose. It also allows me as many preAlerts as I wish, and audible or emails...
I always put the actual appt date/time in the Title, otherwise you won't know what the alert means.