As years go on, this will become unmanageable, especially with more than one kid. I keep only things that show some extra ability or achievement, spunk or personality. I've only kept two drawings so far for my son who is pushing 4. Everything else goes to recycling. Stuff they worked hard on goes on the fridge for a while regardless of ability; when they forget about it, it's recycled. I've taken photos of art and craft projects my daughter did, when they actually represented something presentable, but eventually things have to go. In the movies, I've seen the newly minted adult moving out of their parent's home get a box of their keepsakes, not a storage pod. I use that as a guideline.
Digital clutter will also be an issue, who can sort through hundreds of 'art' photos? A few 'best-of' items per year would be plenty for an average kid (IMO).