I will say that I have misplaced and forgotten about a lot of checks myself. When my person died, I lost about 6 that were issued to me by the courts for my court appointed work. It was a few thousand dollars. Luckily they replaced them. A couple of times the clerk of court called me to check on them - which was very lucky for me.
I just found a check today in a pile of papers (personal check to me for picking up something for a friend) that is over a year old. I will just tear it up and go on.