1, causing diseases
We may not know that there are countless bacteria on underwear that don't look dirty, and even leave stains on urine and feces, which is very dirty. If you wear such underwear for a long time, it will inevitably infect the male reproductive organs and even bring them into the female body, which will cross-infect each other and cause many diseases. So it is irresponsible for a man not to change his underwear.
2, there is an odor, affecting the image.
Although men are used to being called smelly men, they do not advocate such stink, because it is based on damaging their health. And if we sit together, we really want to whisper, but we are choked by the smell that we can't see through, which is very detrimental to our personal image. I believe no one likes to associate with such a man.
Therefore, men can not wear underwear on the basis of personal hygiene and have enough rest conditions under appropriate circumstances. At the same time, if it is necessary to wear underwear, underwear should be changed regularly on weekdays. For example, if it is obviously yellowed, damaged or smells after washing, then don't wear it again. Don't think that you can make up your underwear just because you can't see it. Health doesn't allow you to make up.