I have seen dramatic improvement in my battery life by using a free app that simply makes a shortcut to my settings so I can switch from CDMA/LTE to CDMA only, without digging too much through settings. It worked well, until I've seen how my phone can lose all data temporarily, and the likely cause isn't that app, but the constant switching. As it is, I often have to select the setting I choose to use multiple times for it to "stick". I don't want to keep data shut off constantly when I'm not using my phone just to save battery, but I feel it's the only reliable choice. Tips welcome, please!