It is frustrating enough that I don't do it often. But it's a little like gambling, every once in a while you hit it big.
Last summer my wife saw a CL ad that said "huge estate tool sale, bring your truck!". My reaction was, yeah right. We forgot about it and were trying to figure out what to do with our Saturday and she remembered this sale. Where we live is unincorporated and there's little weird streets and little enclaves all over even though it's not a big area. It was hard to find but it was 2.5ac with a 75x65 barn with a huge ranch style house, with a dumpster out front and guys crawling all over the place like ants at a picnic!
The guy was a hoarder, the barn was stacked 10' high with boxes, racks, machines etc with little paths amongst the piles. It was astounding. I could stand in one place and just stare at a pile and see, a/c tools, sheetmetal tools, woodworking tools, etc etc, in one pile! The family from LA was doing the selling, brothers, sons, grandsons, all hauling and dealing with probably 30guys pulling stuff outta piles and asking how much? It was chaos and stuff was flying out of there but it didn't seem to make a dent. I was still in the door way, and looked up and peaking out of the pile was a Atlas 7b shaper. From what I could see was intact. Tool holder, vise, ratchet assembly, big belt cover on a funky stand. I immediately didn't want to get too attached because they might want too much. I could do $250, but I'd have justify it to my best half. I flagged down one of the sons and he got his dad, he looked at it and scoffed, "$125". Luckily I wasn't chewing gum because I woulda swallowed it. We literally dug it out of the pile it was in and along with some other things hauled it home. What was amazing was this sale had been going on for 3 weekends before we got there and it was just beginning to clear out enough where you could see what all was there!