Varies from person to person. After my cat died last year I started remembering each and every photo I had taken in different places over the years and somehow I lost track of a single photo (I'm not sure how it never got put in a single cloud photo service but I suspect it's because I took it on a camera, not a smartphone) that stood out to me because I remember it as probably the happiest he ever looked. I felt pretty terrible given of all the digital hoarding I do I couldn't keep track of one stinking picture that would mean more to me than hundreds of 4K movies. I'm a bit more liberal with my picture taking now knowing what I went through after the death of a cat and with people it would be worse.

Funny, as I get older the more pictures I take.

I once thought experience was enough for me, however I've learned that memory fades. I can only recall bits and pieces of things I thought I'd never forget.

There's nothing that jostles my memory quite as well as a picture.

The Google robotic overlord does a very good job at showing you interesting photos from years ago. I started taking pictures and forgetting about them only to be pleasantly surprised a few years from now.