I screenshot my desktop sometimes, and my phone home screen. I also save backups of my browser history every 6 months or so.
The reason I do that is I pretty much have no memorable moments in my life. All my life is my computer screen. I save those things so later on I can go back to them and see the stuff I've been doing at a certain time and feel the nostalgia. Like my desktop is usually cluttered with the stuff I'm doing at the time, or my browsing history will reflect what I've been doing at the time, etc.