How many battery you have for Galaxy S4? The battery came with phone is starting to deplete faster and faster, but, I have a bunch of third-party extra batteries with brand. Among those have been used, Mpj and ZeroLemon are pretty cost-effective. Mugen seems too much for a single battery. Why Samsung phone is requiring changing batteries so often?
I have been using my Galaxy Note II for a few years now and I have yet to see a significant drop in battery charge retention.
I hear these complaints a lot, I am beginning to think it is mainly due to misuse of the phones itself. Running the screen on full brightness all the time, using apps that run the CPU at high frequencies for long periods and repeated charging before the battery is empty.
Without going through full charge and empty cycles some batteries have suffered from degradation. I am not sure if this applies to the lithium batteries in modern phones. Just some observations.
Lithium batteries do not suffer from that sort of degradation. They're entirely different animals. You shouldn't run them flat, and you shouldn't keep them full for prolonged periods either, but in a phone that can be unavoidable. You should also avoid getting them hot.
Simple rule for lithium batteries, charge early and charge often. Apart from that, they'll live for a certain period of time, or about 1000 cycles depending on the battery itself.
The one caveat to the avoid running them flat rule is that occasionally they need to be run flat and then fully charged to reset the battery meter. It can get out of whack leading a phone to give inaccurate battery life readings.
For the OP, I suggest getting a battery life app like GSam which will tell you what apps and services are sucking the life out of your battery. Off the top of my head I'd guess location services using the GPS, it's a big killer of battery life.