The battery needs to be recalibrated from time to time to keep the onscreen battery time and percent display accurate, and to keep the battery operating at maximum efficiency. Watts can substitute the default menu bar battery icon and adds advanced features. Watts menu will behave as the system battery icon menu, and provides some extra options like calibration assistant and other features. Watts will guide you through the process of calibrating your battery. The calibration scheduling can be adjusted for your needs, and even postponed if you want. Calibration dates are automatically logged. All relevant information about your battery is fully available as well as clear explanation of any technical details. Charge cycles, current battery capacity, capacity history log… everything to check your battery lifespan.