The one I bought direct from LG was expensive but still losing. life after 6 mos
How are you using your phone and how do you charge it? Do you use Quick Charge 3.0? Are you a heavy user and does your battery get hot often? The key is keeping your battery between 20-80%, keeping battery temperatures as low as possible, and if possible charge your battery externally to lower the amount of heat and stress on the battery.
I charge my batteries externally using the authentic LG charging cradle which charges slowly at 1.0 speeds with a small laptop cooling fan to help blow cool air at it to keep it cool. I'm cycling through 5 batteries evenly so my battery longevity is much higher. If you don't need to use fast charge, then don't use it. Fast charge = hotter battery. I also recommended having a 2nd phone to use so you can have 2x battery life using one phone for browsing the web, playing games, GPS, etc. and the other as your important main phone.. just use your daily driver as a hotspot or use the 2nd when you're near WiFi.
These USB laptop cooling pads are only around $1.50 on eBay and are effective at keeping the phone or battery cool while charging.. blows cool air onto it. Cool battery = longer lasting battery. Might seem excessive but take care of your phone, it will last and live longer while other people have dying batteries.