For me I dislike having my phone wasting power, I save it for emergencies while in the field. For geotagging I use a dedicated tracker, it is very small, battery life is around 2 days, takes cell phone batteries, can be charged in a car, and can hold around 30-40 days worth of tracking and I can download and geotag at my leisure. Start up times are quick, it takes longer if you are restarting after a very large distance move, but that is just satellite acquisition. It is the Qstarz BT-Q1000XT small. That works for me. Just a different take.
Alan