I have never paid attention to battery maintenance....In 3 years I'll replace the phone...26 years of phones..none of them ever got replaced because of battery. N4, N5 had bad battery life to start with but turned off in a drawer they still Boot and work fine.
I have kept my N6 on charge all day in a vehicle for almost 3 years now... The battery still lasts most of the day. I do not see any difference since the day I bought it.
This XL tho has monster battery compared to the N6 . 90 minutes of GPS and streaming Pandora in the car and it only used 13% .