I recently bought a refurbished iPhone XS in 'excellent condition'. The phone says its battery health is 85%. Apple classifies anything above 80% as optimal, but I know when my old iPhone 7 got to 75%, it became very dodgy. The refurbished phone has a 12-month warranty.
I then thought I'd see how long the phone lasts if I just played nonstop Netflix. We're close to 10% from 100% after more than 6 hours. Is that considered good performance? I did have it on silent, not sure if that's made the test easier on the battery.
I'd be grateful for any technical advice on the above! Thank you.