At least once daily. I don't use it much, but my kid watches cartoons on it sometimes, so that drains the battery a lot. I don't think the overall battery life is all that great anyways.
I charge my phone every 2-3 day depending on how often I use it. It drains quicker when I'm using more apps or media. I plug it in before I go to be and then unplug it in the morning.
I charge my phone every night. However, I make sure to take my phone off the charger the minute my phone says it's got a full charge. I don't leave my phone on the charger for a long period of time because I fear that it'll ruin the battery on my phone and I don't want to have to get a new battery.
Well, since I am constantly on a move(well, back and forth to work and some other things), and I leave my phone open pretty much all the time, though I have Samsung Note 4 that supposely have pretty good battery power, I charge it every night before bed, get ready for the next day. I even put it on charge on my work's desk all day...
My high traffic phone everyone has the number too and carry is about 2-3 days max. But I reject and trash numbers all the time. I must be a target for that guy in Lizben who is trying to scam me into giving him/her my CC info when I know darn well my card is not online and I have them all locked to local charges only until I release them through my bank for vacations.
My real phone that sits on the table for family and the girlfriend...about once a week unless the gal is in extra chatty mode on certain days and them I'm dead in a few days.