Getting teens underwear right is one of those things that doesn't get nearly enough thought. Parents grab whatever's in a multipack and teenagers don't think about it at all until something goes wrong. Teens go through a lot physically. Growth spurts, sport, school days that are longer than they need to be. Teens underwear that actually fits and holds up through all of that matters more than most families realise.
I know a mum who'd been buying her teenage son the same cheap multipack every few months, going through 3 or 4 packs a year. When she switched to quality teens underwear in properly sized, decent cotton, the cycle slowed right down. Same spend over the year, far less hassle, and her son stopped complaining about his gear mid-sport. That's not a minor thing when you're dealing with a teenager.
What teens underwear needs to do is pretty specific. It needs to handle frequent washing because teens don't always treat their laundry gently. It needs to stretch properly because bodies at that age change quickly. And it needs to be comfortable through long days of physical activity and classroom sitting. Cheap synthetic fabric fails on most of those. Quality cotton holds up. Barramundies makes teens underwear in Australian cotton with construction that lasts.
If your teenager is still in the cheap multipack cycle, it's worth trying something better just once and seeing the difference. Teens underwear that fits properly and stays comfortable doesn't guarantee a happy teenager, but it removes 1 small source of irritation from the equation. Sometimes that's enough.