Do you know when you need to launder your clothes? I thought I did, but I learned a few things from the Real Simple When to Wash It Handbook:
Bras don’t come into direct contact with the underarms, so they should be washed every three or four days. However, they need a 24 hour break between wearings for the elastic to recover, so you should rotate them. One way is to line them up in a drawer. In the morning, take a bra from the front, then send it to the back of the line in the evening. If you sweat a lot, you should wash bras daily with a gentle detergent.
Jeans should be washed after wearing them four to five times. To keep them looking like new (or faded just the way you want them), throw them in the washer inside out and use cold water. Avoiding the dryer will help retain color, too. You can send them through the spin cycle sooner if they stretch out, or just toss them in the dryer for 10 minutes. Spandex-heavy “jeggings” (jean leggings) should be washed after every wear so the knees don’t bag.
Dress Pants need to be cleaned after four or five wearings. Since you’re probably wearing them in a cool air-conditioned office, they can be used multiple times, particularly those made of stain-repelling synthetic blends. If they're part of a suit, you should dry-clean both pieces together so one doesn’t fade faster than the other. And remember what your mother always told you--your nice trousers will last longer between washings if you change into your “play clothes” as soon as you leave work.
Jackets and Blazers should be washed (or taken to the cleaners) after wearing them five to six times. Since they're typically put over another layer, like a blouse or camisole, they don’t require much upkeep. However, a jacket can retain odors, so before you put it back in the closet, air it out or spray it with a fabric freshner. Periodically check high-friction areas, like the collar, cuffs, and placket, for signs of dirt. But you can roll up the sleeves (or even pop the collar) to temporarily conceal stains on an otherwise-clean jacket.
Khaki Shorts and Pants will be dirty after two or three wears. Light colored cottons are vulnerable to noticeable spots; you can treat any dirty areas between washes with a stain remover. With stain-resistant fabrics, you can get usually away with an extra wear or two. Never use fabric softeners or dryer sheets on stain-resistant garments, as they diminish the effectiveness of the fabric.
Pajamas should be laundered every three to four nights. Wash them twice as often as you change the sheets, because during the night you sweat and shed skin cells. If you shower before bedtime, you can probably go an extra night or two. However, if you snooze in silk, which absorbs more body oils than cotton, you should switch your sleepwear daily.
Skirts need to be washed after four or five wearings. If nonsilk fabrics need refreshing, throw them in the dryer for 10 minutes with a dryer sheet. You can be more lenient with circle and A-line styles, which hardly touch the body. However, whites and silks are prone to discoloration and should be cleaned after every wear.
Swimsuits should get washed after every wearing, otherwise salt and chlorine will eat away at the fabric and stretch it out prematurely. Hand wash your suit with cool water and a gentle detergent, and allow it to air dry. Even if you only dipped a toe in the water, a swimsuit, like underwear, is an intimate garment that absorbs body oils, bacteria, and odors. Best to wash it every time.
Tops and Dresses should be laundered after one to three wears. There are several ways to keep these pieces in ready-to-wear shape. First, don’t overdo the deodorant; one dab will do you. You can prevent underarm stains with an undershirt or dress shields, and remember to inspect the item closely prior to ironing, which can set stains. Again, whites and silks need a cleaning after every wear. If your dress is formal or semi-formal, it’s best to clean it after each outing, since you don’t want any stains setting during the weeks or months between wears.
T-Shirts, Tanks, and Camisoles need to be treated like underwear and washed after each wearing, because they're close-fitting and oil-absorbing. However, if you've worn it four hours or less you can probably put it away without washing it..