Well I can only speak from my experience having Poly FD, no MAS. Many fractures and to many surgeries to count. I'm feeling it now at 50, which I never thought I would reach. But I was hard on my body when I was younger, very angry about this, sad and self-hating. I did everything you shouldn't do, just to say I could and scare my poor mom almost to death.
Now when you think of living till 70 or 80, or 90... I think we all have different ideas of what living is. some wont call it life if they are restricted to barley getting around without mad pain. Some dont mind at all. FD isn't going to stop anyone from existing, unless the FD swells and squeeze's out a vein or artery. My advice to anyone listening, take care of yourself, recognize that you do have this disease but dont let that define, but do give yourself limits. Now dont be to cautious, you need to experience life and no contact your bones get softer so to speak. I rode skateboards, wrestled, weightlifting "which I am getting back into soon". But if you're younger, please take care of your feet and legs..wake up and stretch every day, it will pay off I promise. I know because I didn't and now it's very difficult.
Good luck everyone, good bless.
Joseph