Re: disadvantages of not wearing underwear
It's more of a basic human personal hygiene item. Some things we do everyday, and changing your underwear is one of them. There are many good reasons.
They come in big packs, 12 at a time, and they are cheap. Two, three bags, bought at once, will last you 2 years.
If you meet a girl/mother/doctor/dude, all will want you to have them on.
I you ever get a skid mark, you can just throw the drawers away.
I have two son's who I've had this conversation with too. I also made them shower, brush their teeth and hair, and wash their clothes and dishes. They came out fine...