A method for operating a hybrid electric vehicle having a hybrid system comprising an electric machine and at least one energy storage module using a hybrid control module, comprising: establishing a predetermined service life target in a selected metric for the at least one energy storage module; establishing a maximum operating temperature for the at least one energy storage module; operating the electric machine such that an actual operating temperature of the at least one energy storage module does not exceed the defined maximum operating temperature; defining a static maximum operating temperature such that the maximum operating temperature may not be modified to exceed said static maximum operating temperature; defining a static minimum operating temperature such that the maximum operating temperature may not be modified to fall below said static minimum operating temperature; calculating a first indicator indicating progress of the past operation of the at least one energy storage module toward the predetermined service life target, wherein the indicator is calculated using a plurality of actual observed values of one or more usage parameters observed during past operation of the at least one energy storage module; modifying the maximum operating temperature for the at least one energy storage module based upon the first indicator; modifying the static minimum operating temperature and the static maximum operating temperature to increase their spread when the length of time the system has been in service increases; and operating the electric machine such that the actual operating temperature of the at least one energy storage module does not exceed the modified maximum operating temperature. establishing a predetermined service life target in a selected metric for the at least one energy storage module; establishing a maximum operating temperature for the at least one energy storage module; operating the electric machine such that an actual operating temperature of the at least one energy storage module does not exceed the defined maximum operating temperature; defining a static maximum operating temperature such that the maximum operating temperature may not be modified to exceed said static maximum operating temperature; defining a static minimum operating temperature such that the maximum operating temperature may not be modified to fall below said static minimum operating temperature; calculating a first indicator indicating progress of the past operation of the at least one energy storage module toward the predetermined service life target, wherein the indicator is calculated using a plurality of actual observed values of one or more usage parameters observed during past operation of the at least one energy storage module; modifying the maximum operating temperature for the at least one energy storage module based upon the first indicator; modifying the static minimum operating temperature and the static maximum operating temperature to increase their spread when the length of time the system has been in service increases; and operating the electric machine such that the actual operating temperature of the at least one energy storage module does not exceed the modified maximum operating temperature.