A medical system, comprising: an implantable medical device having: an energy source operatively coupled to and powering said electrical circuitry, said energy source having a longevity characterized by a depth of discharge representative of a first stage of discharge, a second stage of discharge and a third stage of discharge; and electrical circuitry operatively coupled to and being powered by said energy source, said electrical circuitry being configured to calculate a remaining longevity of said energy source; and a display, operatively coupled to said electrical circuitry, configured to display in graphical form using a scale length representative of a time between said first stage of discharge and said third stage of discharge; a first portion of said display between said second stage of discharge and said third stage of discharge being indicated in a first color; a second portion of said display between said remaining longevity and said second stage of discharge being indicated in a second color; a third portion of said display between said first stage of discharge and said remaining longevity being indicated in a third color; and wherein said implantable medical device is capable of being configured to deliver a plurality of electrical activities; wherein said electrical circuitry is further configured to calculate a remaining longevity of said energy source separately for each of said plurality of electrical activities; wherein said energy source has a predetermined expected longevity for each of said plurality of electrical activities; wherein said display is configured to display, for each of said plurality of electrical activities, in graphical form an indication representative of said remaining longevity compared with said expected longevity. an implantable medical device having: an energy source operatively coupled to and powering said electrical circuitry, said energy source having a longevity characterized by a depth of discharge representative of a first stage of discharge, a second stage of discharge and a third stage of discharge; and electrical circuitry operatively coupled to and being powered by said energy source, said electrical circuitry being configured to calculate a remaining longevity of said energy source; and an energy source operatively coupled to and powering said electrical circuitry, said energy source having a longevity characterized by a depth of discharge representative of a first stage of discharge, a second stage of discharge and a third stage of discharge; and electrical circuitry operatively coupled to and being powered by said energy source, said electrical circuitry being configured to calculate a remaining longevity of said energy source; and a display, operatively coupled to said electrical circuitry, configured to display in graphical form using a scale length representative of a time between said first stage of discharge and said third stage of discharge; a first portion of said display between said second stage of discharge and said third stage of discharge being indicated in a first color; a second portion of said display between said remaining longevity and said second stage of discharge being indicated in a second color; a third portion of said display between said first stage of discharge and said remaining longevity being indicated in a third color; and wherein said implantable medical device is capable of being configured to deliver a plurality of electrical activities; wherein said electrical circuitry is further configured to calculate a remaining longevity of said energy source separately for each of said plurality of electrical activities; wherein said energy source has a predetermined expected longevity for each of said plurality of electrical activities; wherein said display is configured to display, for each of said plurality of electrical activities, in graphical form an indication representative of said remaining longevity compared with said expected longevity.