A:Answer On your phone go to Settings -> Battery -> Battery Health -> And check the Maximum capacity (this percentage shows how much charge your battery can hold, if it says 100% then your battery can hold a full charge, if it says something like 85% then its aged and can only hold 85% maximum charge as batteries die over time) if its above 80% then you are most likely ok, if its under 80% then you should most likely replace it, and for tips to make your battery last longest then I'd recommend charging it to 80% and stop charging, and plug it in whenever it reaches 20% or below.