I just do it because I would never remember what went where. I have some jiffy pot seedlings that survived the frost at the end of March and I have NO IDEA what they are.
I am soooo low tech that I just write down on pieces of paper which bed it is, and what's where. I have some perennial beds, and that helps keep the number of scraps of paper more manageable.
So I'd show you what I have, but it would just look like a pile of paper on the counter.