What Sco said.
Dont you wish you were a fly on the wall, watching us? Your multi-faceted little eyes would see us poised with our mega buck "investments" (detectors), sure that every place we can put a little logic to will yield up inestimable treasures.
I dont know how many old houses and other sites Ive detected that have offered up doodly. I KNOW they have to be good because they are OLD, right? Sometime its the oppostie - all the usual places hold all the usual goodies. Trouble is, we are searching square inches and we are usually pretty unsure of even that. Yeah there was a house here. Somewhere. Or maybe it was a barn and it was over there... I think.
But was it the house of a broke-bacon farmer or share cropper? Maybe the home of someone well-to-do? Either way, the result could be the same. They either had no money to lose or they kept what they had in a purse, inside of pockets far deeper and more sturdily contructed than any we have today.
The only way to know what a site has to offer is to grid and log the site. You will either find the goods or determine that it is, indeed, barren. Wishing for more than that because some spot may be old is only false expectation. Things are where you find them, so search methodically and with patience until you know the facts:
The goods are there... or they arent.