The correct fit is important when it comes to bras. Gaps or overflows in cup sizes, and too tight or too loose band size can be issues if fit is not properly determined. Straps should not do the heavy lifting either. The band should fit tightly enough that the straps are basically just an accessory and not a necessity. Underwires should lie flat on the chest, and cups should not be puckered or wrinkled in appearance. On the other hand, cups should not overflow. Spending the time to have an expert measure and determine your size is very important.