My old 5DIII is now in the hands of Wikimedia UK meaning that they now have a full frame camera. While its a decent camera there are some catches. It has been through about 42K shutter actuations or a bit under a third of its expected life. It has had zero maintenance during that period (no sensor cleaning for example) and not exactly spent its time indoors as a safe studio camera. Its been as far north as Dunnet Head, as far south as Sandown, as far west as Delabole, and as far east as Norwich.
That said with the low light performance you can only get from full frame, good autofocus and 22.3 mega-pixels it still have as a lot of use left in it. The real limit it is going to hit is lenses with WMUK currently only having 2 lens that work with it both at 50mm. While there are “50mm only” adherents it is rather photography’s equivalent of iron-man mode.