Pajamas: swap out your p.j.s twice as often as you change your sheets. Unless you shower at night. If you shower nightly before bed then you can wait a tad longer.
Skirts: refresh non-silk fabrics with a 10 minute spin in the dryer with a dryer sheet. A-line skirts are pretty lenient, but white skirts should be cleaned every wear.
swimsuits: after every wash since the chlorine is so damaging to the fabric. Let air dry.
tops/ dresses: after 1-3 wears. Too much deodorant can also stain the fabric. Whites and silks need cleaning after every wear.
tees/ tanks/ camis: after every wear because they are worn so closely to your skin.
Hope this handy little guide was helpful!