Warning: Noob here with noob questions. A local pawn shop has a Canon 580 EX II for $199.99. The flash test fires just fine and all the functions seem to work. It also looks brand new. The only wear marks I could find was one small little line on the "foot?", where it has obviously been put on a camera at least once. Would I be wrong in assuming that any flash has a "life" or number of times it will fire before eventually going bad? I understand it's probably not a set, or known number just something that will not last forever. If so is it just the bulb that burns out? If so can that be easily replaced? I'm just wondering all this because it looks like whoever owned it previously took very good care of it, but to my knowledge there's no way to tell how many times it has been used or how many times the clowns behind the counter have pressed the test button and blinded each other (something they so kindly demonstrated for me while negotiating a price). I would hate to buy it and use it just a few times and then have a $200 paperweight. Is there anything else I should look at or test before I purchase it? Any other info or opinions are welcome. Thanks!