Hi, JT!
I have bought both used and new equipment on eBay and been very satisfied. However, I always factor into the purchase the cost of a check-up by my local u/w canera tech. That generally means, to me, that the item must be at least $US 60.00 less on eBay than in, say, a camera shop or mail order from NY.
I have never bought an u/w camera on eBay that has been used, but I did buy a new Nik V to replace my older Nik. It was new in the box with the US warranty. It checked out perfectly and I have used it with no problems.
I have also bought a Nikon Strobe and several lenses. All were "bargains" compared to a new purchase and all were completely satisfactory. One thing you need to do is ask the seller questions:
(1) Did you buy X new? If so, when? Do you have the receipt?
(2) Does it have a history of flooding or repairs?
(3) APPROXIMATELY how many dives was it used on? Salt or fresh water?
(4) Why are you selling it.
Of course, you then need to depend on the honesty of the answer. Most sellers will allow you to return an item, but then you may be out postage both directions. The equipment that I have bought has generally come from photo stores that want to get rid of inventory--the Nik V that I got was the last one in stock and they were out of the Nik V business. I got it for $US 300.00, a real bargain; it cost me another $US 25.00 to have my camera tech check it out. The bill was so low because he could see instantly that it was new and had never been used. Oh, yes, that Nikon, USA warranty is nearly worthless: unless you can prove, beyond a shadow of a doubt, that the Nikonos was the problem, they will not cover repairs.
So, my advice to you is like they used say on NYPD Blues, "Be careful out there, folks!"
A second case is buying used equipment from a camera store. If they will warranty it, that will probably be fine. The trouble is that most stores will not risk your screwing up the camera/lens, etc.
A third case is buying something from an acquaintance. This probably comes under a special case of something from Poor Richard's Almanac: "Neither a borrower or lender be[especially when friends are involved]." If something bad happens, the friendship will probably be destroyed.
You asked about equipment wearing out, too. The answer is yes anything that requires two mating surfaces to move against each other can suffer wear. Cameras are filled with such surfaces. Cameras also have electronic components that can fail. And, probably most important, U/W cameras and equipment can suffer from exposure to water, especially salt water. The extreme of that is a total flood. For any camera with electronics, that is nearly a death sentence. Even exposure that is less than flooding can be detrimental. For example, lenses can have their aperature leaves and pivots become corroded if just a small amount of salt water manages to invade their innards. If you maintain your own equipment well, then their is little to fear. However, if the equipment is used, how much will you know about the degree and quality if its care and maintainance?
Well, if all that did not scare you off, at least I hope it helps!
Scorpionfish
