"Battery Life" is the amount of time before your device needs to be recharged. "Battery Lifespan" is the amount of time until your device battery needs to be replaced.
Tips for maximizing battery life and battery Lifespan
1) Update your device to the latest software
2) Avoid extreme temperatures
3) Remove cases during charging
4) Don't charge upto 90% and don't drained it to 20%
5) Enable low power mode
6) Power off your device when on charging
7) Don't enable location and background services