Re: Charging of Moto g 2nd generation
Assuming that the hardware doesn't fail, you can keep the charger plugged in all year. The charge stops when the battery is fully charged. (If you leave it in long enough - a couple of weeks - the battery will probably be drained enough and self-discharge enough that the charger will come on again and top the battery off.)
It's not a good idea, though, to just charge it whenever - like every night. Charge when it's between 40% and 60%. That will give you the longest battery life. Charging when it's still 90% charged is shortening the life a little bit. Letting it get down to 20% regularly will shorten the drastically. (Constantly using the phone until it shuts off, and doing that every day, will give you less than a year of life - for a battery that you
could, by carefully scheduling the charging, keep going until you don't want to use that old phone any more. I'm still using the original batteries [I always have a spare] with my 10 year old Motorola V551. If there's a chance that the phone will get wet, lost, stolen or broken where I'm going to be, that's a $20 phone, not a $700 Android phablet.)
About the only disadvantage to leaving the charger plugged in is that it wastes a few pennies of electricity a week (maybe even as much as $2 a year) - and that's whether it's plugged into the phone or not, it's just by being plugged into the wall.
Battery University - How to Prolong Lithium-based Batteries