To stop snags: Store suits in shoe boxes or flannel bags.
To avoid discoloration: After swimming, soak white suits in a gallon of warm water mixed with the juice of one lemon and 1/4 cup saltwater. Rinse well. For all other colours, rinse swimsuit well in hand soap and lukewarm water.
To keep elastic from eroding: Since mildew contributes to decay, try to air-dry your suit as soon as you change out of it.