The life cycle of a lithium-ion phone battery is measured in “charge cycles”. A new battery will typically last between 300 and 500 charge cycles—maybe as few as two years if you aren't careful with your charging habits, which is what we are going to help you with here. This doesn't mean that your phone's battery will die. The golden rule is to keep your battery topped up somewhere between 30% and 90% most of the time. Top it up when it drops below 50%, but. Likewise, at the other end of the scale you might think it's best to let your phone completely drain and die before charging. However, you should avoid allowing your phone battery to get below 20%. This, combined with the advice. As a rule, it's best to avoid—as it will almost certainly mean you are charging the battery to 100%—despite the convenience of waking up. No, or at least not every time you charge it. Some people recommend that you do a full zero to 100% battery recharge (a “charge cycle”) once a month—as this re-calibrates the battery, which is a bit like restarting your computer.