An old, tired and worn out battery is part of any electronic devices life span. iPhone batteries become less capable of maintaining there original powering capability after multiple charging cyles and age, which results in a iphone battery randomly shutting down after short durations of useage. The original apple iPhone battery is usually good for about 500 charging cycles before it begins to wear down. How fast you may run through those battery charging cycles will depend mostly on your phone usage and the age of the battery. The age of any battery will also affect the performance of a battery.
Using a iphone 8 battery as an example; with normal usage, a iPhone user can go about two years before they experience problems, such as a sudden iphone battery drain, which excludes the iphone 6s battery recall problem, which pertains to a defect. If your battery power indicator goes from 40-50% to 0 while in use then that's usually a good sign that the iphone battery needs to be replaced with a new iphone battery. The iPhone usually doesn't indicate a alert if your experiencing the iphone battery draining fast. It will just decrease the phone's processing ability. There may also be a warning message if you check into the iphone settings menu for the battery.
Phone apps can also be a real battery and performance killer. Check frequently which phone apps have been using the larger share of your iphone battery life in the last day or two. Then make a decision, if they are really needed of if they can be deleted from the phone or used less often.
If your wondering; how to save battery on iphone, then consider that, the focus should not be about improving battery life on an old battery, since at some point in time, the battery will die, at the end of its life span because of age realated deterioration of the battery cells. It's common knowledge that, by replacing a phone battery stops the common iphone battery drain problem and usually results in perfomance and speed improvements of more than two or three times.
Here a some warning flags to look for;
If your battery is aging and your having problems with performance, such as iphone 6 battery issues, or if you just checked your cell phone and the battery was at 50% and all of a sudden, a few minutes later, your battery indicator is under 15%, then it may be time to get a new iphone battery replacement.
Check Out Our iPhone Battery Replacement Videos