In terms of the results and the psycho-social benefits, reconstruction at the same time as the mastectomy is generally considered to be better.
"Immediate reconstruction" is the term used when the reconstruction is performed at the same time as the mastectomy. "Delayed reconstruction" usually takes place several months after the mastectomy but there is no set time limit. Reconstruction can be performed literally years after the mastectomy. ...read more about What is the best timing for breast reconstruction surgery?