I've never heard of wearing different underwear-styles dependent upon time of day, not to mention I typically wear one pair per day.
I've worn nothing but boxers since 7th grade which of course made track interesting, but soccer wasn't exactly peculiar but I became a little famous for my boxers hanging below my soccer shorts...another part of the style, I guess.
Oh, I forgot...
Typically if it's a dress-up event like a wedding or a formal, I go free. I'm not exactly sure why, I just do. I guess I don't like my boxers bunching up. hope that wasn't too much info..
