Before being married, my rule of thumb was no less than 10 years younger or older.
Mr. Hardcock though, he would be the exception to my rule.
I know there are many factors that can cross the age boundaries, but it is nice to have someone who can relate to the time when I became of age. Take for example -
Prince's Purple Rain- it is a lot easier talking to someone who lived through it than someone who watches VH1 rewind and looks like a deer caught in headlights when I mention anything from the 1980s.
Then there are other factors, would I still be attractive when I am 65 and my partner is just early 45? That is when a woman better pray the male is more in the relationship for love and not still so visually stimulated.