We left just one big cedar unmarked at the mill pond last year. By the time we got back with the gear, it had drifted and took out a prop on a volunteer's boat. That taught me you need to tag everything you see on the first pass, even if you plan to pull it later. Currents change, water levels drop, and you'll lose track of them. A cheap buoy on a long line is way better than paying for a new lower unit.
Man, that's a tough lesson to learn. It really shows how key it is to tag things right when you see them. A bit of work now can save you from a huge headache later.