When you say "readings," do you mean just the display number itself, or that the battery will run on an inaccurate charge? i.e. Would the inaccurate number being displayed be the actual life of the battery on that charge, even as it fluctuates?
Would calibrating my battery monthly prolong its actual life, or does it solely have to do with the accuracy of the readings displayed in the menu bar?
And you forgot to say, how often do you calibrate yours? : )