Most Helpful Guy
You have to look at the total package. If she is a really fit 55 year old who can exercise with me and has a great personality/is fun to be with, I don't care how old she is. Also people's chronological age is not always on a par with their biological age or their level of maturity.
Generally speaking, though, I would say 10 years older would be my limit.
Most Helpful Girl
Not interested in younger men for anything other than models for my anatomy-studies for drawing, although some of them look way older than they are, and happen to be quite good-looking. I have a two-year younger brother, and even if I were to go younger, I could not go younger than him.