I have an old Edge 510, battery that now only lasts maybe 6-7 hours after 9+ years of use. It used to be good for 12-14 hours. I started with my iPhone4 and mapmyride which would drain it in 6 hours. I only need the distance, cadence and HR data to make decisions on drinking, slowing down on a climb or changing gears. I would never go back to a cell phone for gps and data. I am looking at getting a new Edge 1040, if I can get my miles up by end of summer for some longer rides. A bigger screen would help my old eyes. My left knee has prevented me from surpassing 50 miles the last few seasons. I definitely prefer having a charged cell phone, which stays in my Gearjammer saddle bag. I tend to ride known routes, so I am not getting lost, but I love looking at the performance data afterwards. Also looking at getting a Garmin watch for walking/jogging days.