On the used camera market, the question you always see is “How many actuations does it have?” It’s a perfectly reasonable question to ask. It’s no more weird than wanting to know how many miles the used car you’re about to buy has done. The more it’s done and the more it’s been used, the less life there’s likely to be left in it, right?
While some manufacturers don’t post the numbers publicly, pretty much all cameras come with some kind of expected shutter life count. These days, that number hovers somewhere between 100K and about 300K depending on the level of camera you buy. The Canon 5D Mark II was rated to 150K when it was released back in 2008. But this one, acquired by YouTuber FoxTailWhipz has over 2.2 million actuations and is still going strong.