Bras that have underwires are particularly vulnerable to poor storage practices and incorrect washing procedures. To maximize the life of your underwire bras:
Never wash them in a machine
Never dry them in the dryer
Always store them carefully, without bending or twisting the wire
Basically, with an underwire bra, your goal is to never twist, stress or break the wire. Anything that might cause strain on the wire is a no-no - it could break the wire, change the way the bra fits or otherwise damage the underwire bra.