Remembering phone numbers.
Rewinding your cassettes with a pencil.
Brushing your velour shirt.
Putting a penny on your needle head so it wouldn't skip on the record.
I did not memorize many because I never had many friends, and of them, I would look them up if I had to call them. I think a lot of my memory contained events that I experienced more than anything memorized. I hated being assigned to memorize anything.
Many years ago when I was in high school, I had a lock on my locker, so I had to remember my lock combination. Of course, since I had to use the combination most every day, I had no problem remembering it. Just a few weeks after graduating from high school it struck me that I could no longer remember the combination.