All the time? Nonstop? Nobody needs to wear underwear all the time.
A boy does not need to wear a girl's underwear if his crouch is getting big because the underwear is not designed for them.
If you are male, you probably don't need to wear underwear and spandex at the same time; just wear spandex shorts. If you are female, you can wear a thong, particularly if you need to have a panty liner or tampon in.
Depends on the woman. Some women go "camando" all the time. I have found when I am wearing my kilt it is more comfortable without underwear.
Stop. Buy your own or wait until you are on your own and wear your own underwear; wearing a woman's personal underwear is gross; your mom's even moreso.
Wear underwear fit to your body or not bunched in any areas. You don't need to get a wedgie while running or working out! All you need are regular underwear.
Uhh...boxers are underwear...
Some do some dont some dont wear any underwear
Oneleg at a time
No. Men and women wear underwear to bed all the time and nothing bad happens to them.
Most of the overall population has the idea that they HAVE to wear underwear to be normal, but in reality underwear is only a recent invention, and because most people shower regularly there is no real need for it in these modern times. Most men "go commando" from time to time; some men never wear underwear. It is mostly a matter of comfort and support. I prefer freeballing because I enjoy the freedom associated with it.
at that time they did not have them for men so no
The best way to wear underwear for 5 days is to wash it. Underwear was invented so you can wear your larger, outer clothes for five days, while you only need to wash your small underwear every day or two.