I have kept a form of photo diary for years now.
I struggle a lot with my memory due to my mental health issues.
And it helps me remember what I experienced.
Also, it helps me capture the good moments.
With depression especially, those are so important to cling to.
In addition it helps me practice gratitude.
For the cola in my cup, the beautiful flowers, the bird on my screen saver (my middle name is a little birds name) and so on.
Also any "hygge"/cozy moment, I try to capture it for my photographic treasure box.
It has saved me more than once to look back on my photos.