For most women, the implants in a breast augmentation don't actually "drop." Fullness decreases in the upper breast for two reasons - resolution of swelling and relaxation of the muscle. Initially after a submuscular breast augmentation, the pectoralis muscle is tight. This compresses the implant and give the impression that the implant is sitting high. Over time, the muscle relaxes and stops compressing the implant. From the outside, this appears as though the implant "drops." Bra straps can help reduce swelling initially, but are usually not necessary for a standard breast augmentation. However, there are times when a bandeau is very useful! If significant capsule work has been done, capsular releases have been performed, or constricting bands in the breast have been released (such as a tuberous breast) - then adding downward pressure is may be desired.The bottom line is that your plastic surgeon is advising you to wear a bandeau for a specific reason. No one on this forum knows your story, was present in the operating room, or can tell you to wear or not wear the bandeau. The best answer is to follow the instructions of your plastic surgeon, and contact them if you have further questions.