One person at the phone store had told us to let it drain and only charge it until it's charged. In other words, his advice was never leave it plugged in overnight. This might be true, but I plug it in overnight. I also plug it in the car fairly frequently. 

I don't dare drain the battery.... I recharge every evening....without fail!!!

I get advice on both sides of this issue, I just plug it in when i think about it or when it really needs it.

I was just told the let the battery completely drain ever month or so. Then recharge fully.  In the meantime ... let the battery get to about 10% before recharging.  It will make it last longer.  

I think that was true on the older phones...but I guess it depends on what kind of phone... It is usually half charged whenver I get a new one, and I charge it any time.  I also shut my phone off at night and leave it charged all night... Doesn't seem to hurt it... mine is an iPhone

Your have some good advice. I recharge my phone at the end of the day.

not good to over charge the battery

Better to drain it then leave it plugged in, but i dont always seem to follow my own advice

From what I've read - drain all the way then recharge - IMO however, it doesn't really matter since you'll be getting a new phone and/or battery within a year anyway!

I just read somewhere it is not good for your lithium battery to go below 25% as it lessens it's recovery. Might want to look that up. I was surprised.

Whatever the user manual states!! 

I follow the advice of the "expert" who has sold me the phone.  

Wayne and Jean Marie Zuhl - it is recommended that we drain the battery for the brand new phone - read somewhere...

With Iphone the first time you have to use whatever charge you got till the end and only after that recharge. I try to keep my phone( as the rest of my devices) fully charged most of the time. 

I keep my phone plugged in all the time and have had no problems, but now that you asked the question I will double check with the retail consultant.

 It used to be... not anymore.

I charge mine at nigh...seldom goes dead before and it has been 4 years with no battery usage lost

I follow what they told me when I bought my phone. I don't plug it in at night.

My people said drain it. 

I hear varying ideas on this. I have found battery will start draining faster just short of the 2 year contract date. I can limp it along or for a couple of months but think they plan it this way so we want to trade up sooner. I charge mine when ever it needs it, at home, office, in the car or my portable phone charger. There is no routine except at night on the charger.

Letting it drain is the best policy.  It reduces the wear and tear on the battery.  Leaving it plugged in overnight shortens the battery life.  Older batteries had a "memory" so this was a much bigger issue in the past.

Wow, lots of interesting answers.  I just plug it in overnight and if it's low in the car.  I don't treat new or old batteries any differently....-Kasey

New batteries don't have as much of an issue with 'battery memory' as before, so you shouldn't have to worry about draining between charges!

I plug in my phone into the wall and it works!  The telephone company provides the electricity to run it.

I plug mine in overnight, whether it needs it or not!  I also have a Mophie on my phone so that I don't have to plug it in during the day at all.  Thankfully, I don't have any issues with my battery dying during the day any longer!

I would ask the manufacturer.

Batteries have their own rules such as they can only be charged and drained so many times and each battery knows this. Just jump in & use

You have lots of great answers here

Wayne and Jean Marie Zuhl Since we stopped using Nickel Cadium batteries that had a memory, the new Lithium Ion batteries don't have this problem.

Clueless, keep it charged to keep in contact works for me!

I have always believed it is better to deplete then recharge.

drain it to keep battery strong....

Lithium Ion batteries do not have memory. However they do have an explosive personality, meaning you should leave them in the mailbox in front of the house when you sleep.

There is no need to drain battery, UNLESS your NEW phone has a flip cover. In that case, all bets of off.

iPhone Batteries don't have "memory" like they used to when they needed to drain-per Verizon. I plug mine in all the time, I've had mine 3.0 years and the previous phone 3 years too, no battery issues. That said, do what the manual says.

I plug it in all the time

I have no idea, but I've heard it's better not to keep the phone charging all the time.

not sure these days

I have heard whole bunches of different things on this.. honestly I don't know which is true.

Newer batteries don't have a memory so it really doesn't matter.