What phone do you have now?  Do you have lots of music you what on your phone and Ipad?   Do you keep your daily planner on your phone?  We just got our first smart phones 3 months ago.  We have had an Ipad for 18 months prior (bought for fieldview and wireless internet).  We picked Iphone because of those things.  My wife and I have our schedules automatically sync to all 3 devices.  We have all our music on all 3 devices, but my wife doesn't use it.  I have had great battery life on my Iphone 5 if I leave the wifi turned off and spend no more that 1/2 hour on the internet through the day I usually have 25% battery after 16 hours in the field.