I've been using AccuBattery to monitor battery health.
https://play.google.com/store/apps/details?id=com.digibites.accubattery
I only have a couple months of use so far but here's how my Z2 Play is holding up.
https://play.google.com/store/apps/details?id=com.digibites.accubattery
I only have a couple months of use so far but here's how my Z2 Play is holding up.