I chose +/-10 years. Hubby is 6 years younger than me, so -5 wasn't an option!
I have to agree with what everyone has been saying, that dating range is fluid depending upon the individual personalties involved. As long as people have common interests and are compatible that is all that really matters.
Besides, it really depends on how old you are when you start. Somebody 10 years younger than me isn't even legal!