Batteries don’t live forever; the constant charge and discharge reduces the lifetime of the battery reducing its maximum capacity. This is a normal occurrence in anything that uses a battery. The fix is quick and easy with affordable prices. In worst cases the battery will swell up affecting the trackpads click and touch sensors. This has an increased risk of spontaneous combustion, or explosion. A way to know when a battery service is due, the device will push a notification titled “Service Recommended”. If you can use your trackpad most likely the battery has expanded to the point where the trackpad becomes dysfunctional. Then this is the time where you should have the battery replaced and get your device running as good as new.