It's odd that although we use so many products that clean better and faster, that we don't spend LESS time cleaning... we spend MORE! I think there's something to this theory - we are TOO clean, and it probably makes our immune system less responsive when threats do occur. At the very least, listening to TV commercials remind us of how every speck of invisible dirt demands our strictest attention (and their product), is gonna make you a neurotic mess.
That being said, clothes should be washed.
Waste creates opportunities for bacteria and other bad guys to damage your body. Your body has ways of disposing of this waste, which go on even when we don't realize it. (Shedding old cells, sweating, etc.) Clothing gets in the way of these processes, and traps waste materials against the skin. Your clothing does NOT have a way to dispose of waste, so it makes sense to wash them regularly. And it makes sense to wash your body regularly (though not TOO often), to keep the waste moving on its way out.
Personally, I don't think it's necessary to wash every article of clothing every time I wear it. A t-shirt gets a good 2-3 wears unless I've done something to make it visibly dirty or noticably smelly (like exercise). Jeans may get 3-4 days without a wash, provided the same. Boxers, undershirts and socks get one wear per wash, because people really notice if you smell like butt, pits or feet! If you insist on smelling totally laundry fresh, so that people who expect a neurotic level of cleanliness are happy with your presence, wear fresh clothes. Job interviews, going to church, and visiting a physician, are situations where it's socially expected to be especially hygenic.
Edit: Also, if you're going through puberty, it's basically a FACT that you smell worse than you think you do. I'd suggest erring on the side of TOO clean, at least until you're done with high school.
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Sainte atha ma u Hrair, kan zyhlante hray u vahra ma hyaones.
My heart has joined the Thousand, for my friend stopped running today.