I bought a lot of things online for my FiL and that, together with general assumptions, mean that I get a lot of bumf about stairlifts, chairs that throw you out of them, incontinence pants etc. I need none of them yet, I know where and what to look for when I do, and the assumption that I do b****y annoys me.
I think we can make a difference simply by the way we behave. I know that many people have health problems that make mobility difficult, but my mum always paused when she stood up and put her shoulders back - it took years off her.
So standing as upright as we can, walking as firmly as we can and not shuffling or drooping any more than we can help should at least give the impression that we're fit and youthful. A lot of it is down to our own attitude as well as other people's.