John says his smartphone's lithium ion battery doesn't have very good battery life at all. Leo says that is an odd development. Batteries are limited to about 500 charging cycles. You keep about 80% of your capacity throughout the life of the battery. Go with manufacturer brands. Anker, though, is a good third party brand.
What could be affecting John's batteries is how he's getting them since he can remove the battery and use another. Temperature can affect the battery life. If John keeps his phone always plugged in, he'll preserve his cycles too and that can make his battery life longer.
For tips on charging your Lithium Ion batteries, visit this article at Battery University.