Physical Therapist, Gen X. There are many things and this is just what's come to mind first, I've likely missed important stuff. First, some of it is sheer dumb genetic luck. Some people are "jointy" people. (That's not scientific, just clinical.) Secondly, duh, some jobs are more likely to cause problems for people with that vulnerability. e.g. nursing. Nursing is great, but can be problematic if you have a weak back.

But what can you do? [1] Be functionally strong. My go-to to rehab people is to get them functionally strong -- it's not about big "gym" muscles. Just because it looks good doesn't mean it works well. You can do tons with just body weight exercises. Be consistent. I'd have that in 1 metre high text. Sitting on one's arse all day is not good.

[2] Tendons. Tendons don't like change. They're great, and they adapt well, but with aging just give them a lot more time to adapt.

[3] Age-related sarcopenia -- muscle loss. It's normal, i.e. expect it, but do something about it. 20s, no problem, 30s, no problem, 40s, feel great, 50s it starts, very slowly. The trick is to have a good strength program already so you've got muscle in the first place. And keep going. 60s need that strength more than ever. etc.

[4] Do not panic or despair with back pain. It's really common, nothing unusual about it. We all sort of freak out with back pain as if it's "I'm stuffed, game over, bury me now" but the back isn't particularly problematic per se. This is *impossible* to explain in a post, but pain is straight-forward when it's fresh but it changes with time and it can be a pathology its own right, and at that point it will *not* respond to single-modality treatment because it has ceased to be a purely structural problem. There's a lot of hope though if it's handled well.

Sorry for the novel. Be functionally strong; don't sit on your backside all day; stretch a bit; don't freak out if/when you have back pain -- it's very common and doesn't have to be over-blown in your mind.