I live in what is essentially a bungalow - but the master suite is upstairs. So far, at 81, I have no problem with going up and down the rather steep and shallow-stepped stairs, and like others I never push myself up with my hands on the arms of chairs when I rise - I've been making a point of that for the past 20 years. In my 40s and 50s I used to go to step classes and was amazed, after I moved to a place where there were no step classes, how strong they had made my thigh muscles! I haven't lost that yet either. I also do a lot of tai chi which keeps me supple and aware of how I'm moving. Sooner or later, though, I'm pretty sure weakness/infirmity will strike, as it does us all eventually, but I intend to give them a good run for their money! Stairs or no stairs, I don't think it matters so long as you are mindful and compensate. One advantage of no stairs is that you can't fall down them!!