I generally advise my patients to wait a minimum of 3 months and preferably 9 months prior to investing in a whole new brassiere wardrobe.
A post-surgical breast garment is generally recommended following surgery (for 1 to 2 weeks). After about a week, I like for patients to wear a sports bra. After about 2 months, you can be sized for the most appropriate fit at Victoria's Secret or other bra carrier.