A few years ago my parents presented each of us children with a book containing family Christmas pictures every year since they were married ... it is such a treasure and so fun to go back and see how our family has changed over the years. I've started that tradition and have saved our cards so we can look back and see how our family has grown.
My sister Celene took that idea even further and has saved pictures from each Halloween of her kids in their costumes! So fun! Last year I played "catch up" and found pictures of my kids each Halloween and made a digital scrapbook page for each year (of course, paper scrapbooks work as well!). I print out the images and keep them in a spooky black scrapbook that I can add to every year. We displayed it with our Halloween decor last year and I can't tell you how many times my son wanted to sit and look through it! Even if you only had time to slip a picture in a photo album - it would be a fun tradition to start!
Here is what we did: