I’ve heard this to be the case. But I’ve also heard that the only thing to worry about is, when the phone is new, make sure you allow the initial charge to deplete all the way.
So, what’s the straight dope?
No, it’s the best way to use your phone.
And, DO NOT discharge the battery all the way - that’s the worst thing you can do for it’s life!
the actual battery charge controller is built into the phone, and will take care of everything for you. the thing you plug into the wall only provides 5 volts DC to the phone and the controller does what it needs to with it.
and no you don’t need (or want) to fully discharge* the battery. Lithium rechargeable cells are pretty well understood by now and the phone hardware knows how to interpret state of charge from the battery voltage at any time.
- in reality, you can’t fully discharge the battery; lithium cells usually have protection built in which will prevent discharging below a certain point. if you truly run a lithium battery flat, you will kill it forever.