Thanks for the advice, this is already really helpful. And no, there was nothing in particular, I was just wondering if it was a definite go or no-go to purchase stuff second-hand. Don't like doing that, because I've made some mistakes in the past with that. That includes buying one of these second-hand hublot watches that a friend of mine used to sell. But after 2 weeks, it stopped ticking. Fortunately, at this webshop
I bought the same model again (because I really liked the looks of it) and that one still works fine.
Anyways, since then I'm a bit more careful with being things off friends. So a while ago, a friend of minde (different one this time) offered his weight lifting equipment, which included the weights and the installation, but he also had some straps, a belt and knee sleeves, which he had already used, so I'm not quite sure about those. Do they wear out? If so, are they expensive to buy new?