Much like I'd feel wrt buying a used car from Avis. With people like me renting them it's probably not a good idea.
Thought so. I concur. I have been tempted a few times but having seen some pro photographers at work, particularly the ones who shoot with their employer's equipment instead of their own, I'd rather just save up and buy new.
I'm somewhat sceptical about buying second hand too, for the same reason. The other problem I find is that, most of the lenses I look at, sellf 2nd hand for so much that the saving I can't see the value in not buying new. For example, I decided that I want to get a 35mm f/2 again (mine was stolen). I've only ever seen them on e-bay, never at 2nd hand dealers. On eBay, they typically go for £200-230. At Camera World I can buy one new for £199
The 200mm f/2.8 L USM II also goes for about £50 less than a new one. For a £600 lens I'd rather just pay the £50 and keep the ability to take it back and get it swapped out if it's a lemon.