Symmetry is a goal that is rarely achieved in breast reconstruction, especially in a single stage. In general, since the breasts are paired structures, if you do similar procedures to each side, you are more assured of getting a higher level of symmetry. This rarely happens, but if you have an implant on one side, you should devise a plan that puts an implant on the other. If you don't want an implant in your good side, you shouldn't have an implant reconstruction. If your surgeon plans things well, and your situation allows it (i.e. no radiation), then it is possible to get very close symmetry but it usually requires at least a coupe of procedures.