Always handle your bikinis with care. Follow the following washing instructions:

Hand wash (within 1 to 2 hours) after every wearing in cool clean water with a mild hand soap
Use just a little of mild hand soap.
Stir/sop your bikini through the water. Do not rub.
Do not leave your swimwear soaking for hours
Rinse out your bikini in fresh water. Do not twist or wring
Do not store wet. Hang out to drip dry your bikini in the shade or better yet flat dry your bikini on a towel or washing rack. While drying, do not expose your suit to direct sunlight. Long exposure to the sun, will fade any colored fabric.

Tips to expand the lifespan of your bikini:

Do not wash your bikini in the automatic washing machine and do not tumble dry. Lycra is a stretchmaterial, which can be damaged in the washing machine and dryer.
Do not bleach
Do not dry clean
Do not use separate stain removers. Those are often very aggressive.
Avoid whirlpools, jacuzzis and hot tubs, especially suits with reflective material can be damaged by whirlpools/jacuzzis.
Do not iron.
Avoid direct contact with suntan lotions or oils. Suntan lotions/oils can damage elastics and stain fabrics.