When In Doubt, Guess Young
It's happened several different times now. The first time was when I joined my mother in taking a dog to the veterinarian. At some point in the conversation, I was referenced as a son, and the vet, startled, exclaimed "I thought he was your husband!"
At other times, I have been keeping an eye on younger brothers and sisters, playing at the playground or other events where the parents are not present. It is here that parents of other children assume I am the father of the kids.
Even from an early age, people told me I appeared far older than I was. Classmates were literally shocked to discover my true age, and I had to produce my license to convince them. "I'll bet you don't get carded for beer" was their immediate conclusion. (This is true, but not because I am older.)
While appearing older has its benefits, I also wonder if this whole "look older than you are" thing stops at a certain age. Or will I be greying by the time I'm 40?
In any event, the practical application here is, unless it's a child, guess on the lower end of the age spectrum. Even if the person is wrinkled, toothless and hairless, guess them to be about 40.