I have the same problem with my samsung. I am not sure if you already got your new phone or not, but I say that you wait till the new samsung s6 arrives! I know that it will come out this month or soon!! What i do is carry around my phone charger and I also have a car charger so my phone always has some batteries. I also turn off the 'location', because that drowns the battery as well.
The battery in Galaxy S3 will only hold a charge for a couple of hours. A new battery is about $40.00 US. I was hoping to get an S6 when they are available (hopefully in April '15). The battery thing is beginning to wear on me. Should I just hang in there? Buy a new battery to use for a month or so? Or, how about a Note 4, today? Thoughts.

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