I disagree with a one-story home unless it's absolutely necessary. I was so smug about my single-story home which I bought in my early 40's. What it did was hide the fact I had a muscle-wasting condition. I thought I was losing my mind as I became more and more tired all the time. In fact, I was losing my leg muscles. When I finally had to walk up steps and on hills, that's when I discovered that it wasn't just encroaching aging or arthritis or burnout. It was a genetic condition (called CMT). I moved across the country, and I have now intentionally bought a house with stairs (GOOD stairs -- wide and even, with railings everywhere) and hills in my yard. I make a point of walking around in it as much as possible, to retain as much muscle strength as I can and to challenge myself to keep fit. If I deteriorate to where I can no longer get around my house or yard, I will hire someone to take care of the yard and move into the first floor only, perhaps renting out the second floor to help with those costs. But in the meanwhile, I now know exactly where I stand (har, har) with my mobility, and I prefer knowledge.