That will be depandant upon on the apps you load onto it, if you load up GPS seeking apps it reduces the battery lif a lot, mine (i phone 4) will go for 24 hrs before hitting the red bar. But I routinely charge it every night as a matter of course. I'm with O2 and have just had my tarriff reduced to £24 per month thats with 200 free calls and 500 texts (i think).