After retirement starts, increased savings are no longer possible to avoid later running out of funds. To avoid running out of funds the only possibility becomes retrenchment. But retrenchment causes immediate pain by reducing the current standard of living. The question is does accepting this pain improve the future standard of living sufficiently to cover the cost of the earlier retrenchment? Other discussions of retirement have failed to consider this key question. This book answers this question by developing The Retrenchment Rule to determine when retirees should retrench.