We define an indexed set (that is, a family) of cost recovery rules, using the concept of an “acceleration index.” All existing cost recovery rules (straight line, sum-of-digits, declining balance, MACRS, etc) are members of this family, and every cost recovery rule is completely specified by its acceleration index. Using acceleration indexes, we describe acceleration relationships among existing rules, and suggest improvements. Examples indicate that this unifying framework would be valuable for designing new, flexible cost recovery rules that may be proposed for future cost recovery legislations and managerial decision making.