This is when I'm thankful for the idea of photo books, or scrapbooks- however you keep your pictures. In the digital age, there are so many photos stored on my computer that I forget about. Every now and then I'll open up the files and scroll through them, but when I have something tangible like a scrapbook page in an album, those memories are fresh and easily accessible. My kids love to pull down my scrapbook binders and look through them, "remembering" each event that is documented.
And hopefully, having those photos really will help them remember.