Most are. But there are few exceptions where I probably will never go again. It really varies a lot what kind a flea market or a second hand shop is. Are there several sellers (people bring their stuff to sell) or is the shop owner the only seller.

One never knows what might turn up.

Although there is a lot of typical flea market stuff out there, there are few surprises too. That really is the most fascinating thing in circling flea markets.