Hi,
I may be able to offer some insight as a Ebay buyer. I just recently returned to Ebay after getting away from it for a few years. I was pleasantly surprised with the watch it feature. I put items on my watch list so that I don't forget them. Let's say I'm looking for a Burberry jacket, or something similar. I end up plowing through hundreds of listings. There will be a few that catch my attention, but I'm not ready to decide on one yet, so I put them on my watch list and then decide. Searching for handbags is even more overwhelming because I'm not locked into a designer and style name name. Instead, I'm searching black leather satchel, etc. So really it's a method of keeping track of things. I do the same thing on other online shopping sites, except I'll use the "cart" feature instead.
Never thought of waiting for an item not to sell to try to get it cheaper.