Got my right knee replaced in 2017, at 59. Had blown it playing high school football, and in 1974, they removed my medial meniscus, instead of just trimming off the torn flap, as they would do today... so... bone on bone for a long time. Was not really painful, but unstable. When they did the pre-replacement X-rays, they said, "That other knee doesn't look much better!"... but, I'd never really had any issues from it. Surgery went OK, rehab was OK... it's still not 'my knee', and I can't squat... have difficulty getting my water skis on... but it's stable! Had an issue with either an infection of the incision line, or just rejection of whatever subcutaneous suture material they used... drained and failed to heal right for several weeks longer than it should have.
During my knee replacment rehab, I had a catastrophic rupture of (what was left of) my left rotator cuff. Got a reconstruction, with cadaver dermal implant... there was nothing left to put back together. Ended up having the right shoulder done 6 months later. I don't have good use of either one, but can at least put my arms above my head now, and can sleep at night now without opioid drugs.
Got my money's worth out of my employer's health insurance that last year, with a knee replacment and two shoulder reconstructions and 3 rounds of PT, all within a calendar year, and retired 1 month later. .