A few years back, around the time the iPhone camera became very good at close photography, I began to photograph Father's Day cards and the like.
Later, when products like “Scanner Pro.app” made it very easy to create PDFs that went to Google Drive, I began to phone-scan correspondence I wanted to keep.
I store the PDFs on my computer. The photos go into my photo library and become a part of our screensaver slideshows. Most of the originals go to recycling.
It would have been great to save more of my mother's correspondence this way, but that would take time travel. We didn't have the tech back then.
It's a good idea.