One uncut sheet that I had in an archival binder -- you know you've been collecting a long time when you forget you have something in your files! April 1920, Woman's Home Companion.
I'm impressed with the record-keeping that many collectors maintain to keep track of what they own. Needless to say, I don't have a system. I always figure since my collection is quite random, and not large at all, I don't have to do that. But that may change!
How many of you have bought something that you already have? I've done that, too!