I found some SL-cassetttes (same as agfa rapid cassetes) with Orwo NP20 last year and they were still good. I just wanted to have the cassettes for my Penti, but since the film was still in it, I had to try it out. With a bit of overexposure and overdevelopement (yes, both) it came out great with only light fogging. That stuff wasn't made anymore after '89, so it was a pleasant surprise for me.
And there was also a 120 roll of NP21 in its original paper packaging (without cardboard box) that I got with a box camera at the flea market. Since the camera can't really control exposure, I just stand-developed it in Rodinal 1+100 and it came out ok, though a little thin.

Film and cameras are made for taking photographs, so I do just that, if there is the slightest chance that it might work. Let the collectors scream in agony, I don't care. If someone handed me the original Ur-Leica, I'd test the shutter and take some photos - without white gloves.