Sometimes I think there is too much bleed through of an actor's personal data and the character he or she plays. Don't know the character's age? Well, how old is the actor? Don't know his favorite food or her favorite music? What does the actor like. In this case the actor playing Dave is younger by a year or so than Flanigan but let's face it, Flanigan doesn't look his age at all. I sometimes think Sheppard favors the stubbled look because it makes him appear at least a little more seasoned than when he's clean shaven, an important point when one is the CO of a military base in another galaxy. I tend to think of Sheppard as being younger than Flanigan anyway.