One of the most useful ways for me to keep track of past medical appointments is by hanging onto old calendars - the ones I write appointments down on.
But I've discovered they're also useful, years later, when I can't remember when I had this or that appointment.
When did I have that hearing test? (It's sure to be marked on the calendar.)
Some important information does get written down in my "health" binder. (I started that habit when I saw the need for a binder for my mother's medical information as well.) It's easier to check there - but I sometimes forget to transfer information to the binder.
I haven't begun keeping track of appointments on the app on my phone. Does it keep a history log where this information could be retrieved? (I'll have to ask my daughter. I know she uses her app.)
But in the meantime, I have this colorful bundle of calendars to refer to, dating back to the mid-1980's... when my children were young.