Apparently I don’t wash clothes as much as other people. Oops.
Clothes: Jeans I’ll wear for about a week. Shirts I’ll wear two or three times before washing, but not in a row.
Shoes: Wear them as often as you want. I have two pairs, one white and one black, that I’ll choose between depending on my outfit.
Pajamas: I’ll usually wear them for about a week.
Bras: According to other answers on this issue, I don’t think I want to reveal how long I’ll go without washing my bras. 
I wonder how often the ladies wash/dry clean their dressing robes.
@coolweather, once a year. I’m always clean when I wear my bathrobe/dressing gown/what-have-you, and I wear it for about five minutes, so it doesn’t need to be washed that often.
I knew a few people that did this, mostly international students in winter. It’s probably a combination of never getting sweaty and not wanting to bring a bunch of clothes with them when they move. Not a big deal unless you smell bad.
Some girls wear a sweatshirt almost the entire fall/winter/spring, so I don’t have any idea how often they wash the shirt underneath if they even have one.
I usually don’t rewear shirts unless I hardly wore it one day or I’m not going out in public much. Pants I definitely rewear, shorts depend on hot it was that day. Winter clothes I rarely wash, most of it isn’t machine washable. I only wear one pair of shoes except for sports.
You will all develop your own scheme and funny enough, a lot will depend on how much (quantity of) and how frequently you want to do laundry. Until I had a laundry machine of my own in my home (many years into my marriage and after graduate school) except for underwear, socks, and fitness clothing, most things got worn more than once between washing. Laundry washing and drying isn’t always convenient or fun.
I’d say that it’s totally okay to wear a sweatshirt/jacket frequently, but you don’t want to be like me in the 6th grade when I’d wear the same ratty pink sweatshirt ALL THE TIME, to the point where a boy in my history class commented on it.
I can see wearing the same pants a few times until you do laundry. I can’t do that with shirts. Some of the medicines I’m on make me sweat. I sometimes change my shirts at least once a day. I wouldn’t wear the same thing day after day.
Jeans, no matter what people tell you, can be worn for a minimum of three days and up to two weeks IMO. Of course people disagree but I do laundry every 2 to 3 weeks and find that 4 pairs of jeans is plenty. Usually I use 3 per laundry cycle.
Shirts, trade em out earlier IMO. I do daily changes, but max 2 days IMO.
I’m a guy, but I am fully of the mind that bras can be worn much more than daily, especially with their ridiculous pricing. Probably not as much as jeans though lol.
You can get away with wearing things like jeans or pants as long as they don’t have distinguishable features about them. And you probably can wear the same shirt a couple of times before you wash it, as long as it isn’t dirty or smelly. Probably just don’t wear it again the next day wait another day after or else wear it when again when you have classes with completely different people so they won’t notice. I’ll be honest I’ve sometimes wore the same clothes twice in one week but it wasn’t the immediate day after that I did it as long as they were still clean looking and smelling. To avoid doing laundry so much or wearing the same clothes day after day I once read an article that said a college should have 2 weeks worth of clothes. since I got to a university where it is super hot and muggy and I have to walk a lot I do usually end up going through a lot of clothes because I have to change at least until the cold weather gets here.
I’ll wear a pair of jeans or cargo shorts for 2-3 days without washing them. I try not to wear the same shirt two days in a row, but it happens occasionally. I’d try to avoid wearing the same shirt for 2-3 days in a row. That’s something that people may notice and find a bit odd. Like Bopper said, if you want it to be simple, just get 7 shirts and rotate them everyday.
Some movers and shakers are choosing a “uniform” and wearing the same outfit, of which they have multiples, every day to simplify life. Google it. Think Steve Jobs turtleneck or a female executive choosing the same white shirt and black pants (she even got a deal for buying in bulk). Seriously. 
Like others said, jeans or pants can be worn about 3 or 4 times before you wash them. Shirts depend because they’re more noticeable. I usually rotate shirts after wearing them at most 3 times (never in a row). I will only toss a shirt after one use if I sweated a lot (I live in Florida).
No one cares about shoes so you can wear them as much as you want.
I will toss a pair of pajamas in the hamper after four nights of wear. You don’t do anything in them besides sleep so it’s no big deal.
For bras, I wash them after 3 or 4 wears (unless I sweated a lot). You’re not supposed to wash bras too often because they will eventually lose their elasticity (and they’re expensive). In fact, I hand wash my sports bras.
Bra Tip: If you wash you’re bras in the machine, have them in a little protective washing bag. You could order it, or you could use a pillow case (like me) and tie it. It saves you’re bras from damage. It’s really frustrating to wash your bras and then find out that the underwire got bent, or they’re tangled in a knot, or that one of the hooks is bent in a weird position and can’t be fixed.
I’ve worn the same clothes 2 days in a row because I had alternating classes every other day (MW(F) or TTh) with different people in each class, so nobody could tell that I was wearing the same clothes as the day before.
Good bra tip @FLartkid29 , also, never put them in the dryer and they will last much longer, even years.
Lots of different opinions here about what is dirty! We have this issue with my oldest son who does his own laundry, but also feels that once an item opr towel has touched his body, it has to be washed! Here is my opinion OP, and I’ll go beyond clothes:
jeans: as long as they don’t smell, are not visibly dirty. People wash jeans too often, which is bad for them. We wear panties/underpants to avoid having to wash pants daily!
t shitrs: generally these are one and done, but it depends on how long you wore it. If you put it on, go to class and then change when you get home, then wear again.
Sweatshirts/sweaters: until dirty or smelly. Again, the tee underneath takes the brunt of body oils.
blouse: once, or twice if it was a short wear.
PJs: 3-4 days. Most college kids end up sleeping in tees/sweats anyway.
Bra: take 3, wear eacg throught the week 2-3 times. Up to 5, I’d say.
sheets: 1 week!
towels: 4 days
Shoes: take sneakers and a nonsneaker!!
You should change up the outfit routine daily, only bc of social expectations, nothing else.
Actually, have 8 shirts. That way you’re not always wearing the same one on the same day. 