I agree with someone else who commented about the "social' aspect of the estate sales. Same thing with the auctions. Here in Memphis, you will most likely see the same people lined up at the door of the estate sale before it opens. A very large number of the people who go to the estate sales here in Memphis are vendors at antique malls and flea markets, as well as sellers at the auctions, so they're all looking for great things at bargain prices to fill up their booths with. Same thing at the auctions I go to - it's the same group of people. Every estate sale dealer in town (and there's several of them) know me and know what I buy and sell and collect. Some of the estate sale dealers (particularly those with whom I routinely spend a great deal of money) call me ahead of time and arrange for me to meet them at the location of the estate sale before it ever starts so that I can go through and get first pick. The estate sale dealers here know I know my stuff and that I sometimes know more about something than even they do, so it's not unusual for one of them to consult me about something they have in the estate sale that they're not sure about. But, there's a 'circle' here in Memphis, where we all know each other, and we consult with each other about things, where we buy from and trade with each other, where we let each other know about things we know the other collects, etc.
And, by the way, my daughter and I will be having a yard sale this Friday and Saturday, which will include quite a bit of vintage and antique stuff. Everyone loves our sales, because they know we are collectors and always have some really good "yard sale junk" which they can take home to keep and treasure, or take to their booth and sell.