I have lost/forgotten a bunch of tools on jobs over the few years, including expensive battery tools. I'm reminded of this every time I look for my 1000v straight screwdriver that I lost and keep forgetting to order a replacement. I'm sure everybody has lost tools so here's the more interesting question: Have you ever found a tool you lost when you returned to do more work at a job? I once lost some lineman pliers and I searched the attic high and low. No sign of them. I returned to do another job in the same attic a year later and found them sitting on an air conditioning vent.