a perfect world large size women should be purchasing (a well manufactured) bra every 4-5 months, but with proper care a bra should really last up to 8 months. However that is not always practical because of the busy lives most women live.

A good way to look after your big bras when washing machine, hook the bra together and place in a lingerie bag and wash on a gentle cycle and never EVER, EVER put your bra in the dryer.