We go through a lot of clothes growing up and some people just put them in storage or throw them away. There's something better you can do with those clothes, though! Some colleges and LGBTQ+ groups are collecting clothes to give to trans kids who are unable to get clothing that matches their gender.
Not every kid is allowed to buy the clothes they want, even when they reach college. Overbearing parents still try to make gender choices for them and, unless they have their own money, they have to get what their parents buy. That's why the donations are so helpful. You no longer need that dress that you've kept in your closet for months that you know you aren't going to wear, so give it to a trans woman who would appreciate it greatly.
If your college or town doesn't have a thing like this already, talk to some people to get it started. If you don't live in an LGBTQ+ friendly neighborhood, you can just put a number as the information so people have to call to get the location. I know it is a hassle, but not every trans person is out and it can be dangerous if someone who is closeted is found out because they just wanted some clothes to wear in private.
If everyone gave their unwanted clothes to people who need them, I am sure that both the giver and the recipient would be very happy. One person would have less stuff lying around and the other would have clothes they felt comfortable in. Just make sure the clothing is in good condition because even I wouldn't want clothing with holes in them!