I've spent way more
money than my wife really wants to know about on Ebay, easily into 5 figures. For the vast majority of the
gear, it has been way cheaper than discounted new and works just as well. Have done especially well on new
equipment that was surplus to the seller. Typically get new parts for 1/2 what they'd cost from a
chandlery.
I have gotten burned a couple of times, largely because I didn't look closely at the posted photos and/or ask questions or the right questions about the conditon of the parts. The vast number of sellers are honest in their listings and have answered any questions I had truthfully. In fact, most sellers rate the
equipment they are selling way lower than I would have. I'm almost always pleasantly surprized that the used parts turn out to be better than expected.