I always keep it on. Almost all of South Florida gets LTE, so I don't have any of the battery problems from switching between 3g and 4g. I also get better speeds on LTE than from my wifi connection. I use wifi whenever I can, but I haven't noticed that it's that much better on battery usage than 4g is. Display always takes up the lion's share of the battery use, and I keep it around 30% (30% brightness, not battery use. Display usually takes up around 80% of my battery). That's really my only complaint with the TB; the battery is too small, and the screen/display eats tons of battery while not being nearly as bright and clear as some other phones (cough, cough, Droid Charge), but all in all I think it's a great phone.