Updated to ios 8.1 and promises of a toggle to go back to 2g, benefits being less battery drain but no still have only a enable LTE and 3g option - 2 degrees please update or is this a ios software issue?
As far as battery savings go, they say to turn off Bluetooth, 3g, 4g lower the display brightness.... I have my Bluetooth on all the time, I leave 3g and Wifi on, and the display set to auto, 3 years of use on my 4S and now on my 6+ it hasn't made any noticeable issue.
If you don't use Bluetooth, sure, turn it off, you're not missing anything. If you don't use wifi, turn that off too. If you don't use 3g, you can certainly turn that off as well.
But you have a smart phone, turning off all these things makes it no more useful that the old dumb phones - what's the point?
If you're having battery issues, I suggest you may be having issues with the battery itself (iPhone 5 perhaps?) and should seek help from Apple. But if you're a heavy user, I would suggest a battery pack, there are plenty of good ones about.
Or upgrade to a 6+ and go hard all day (its great with ingress!).
Always have display at its lowest and never have bluetooth on, going into notification disable most only leave the main ones messages etc. Siri off, Background app refresh off etc.
Yep 2 degrees with LTE off as 3g default in some areas 1 bar sometime 2 bars like here, but anyway this is a software issue im not getting caught up into the issues of "iphone was made primarily to be used with 3g/LTE" etc even apple forums have this issue pointed out dependent on carrier some say and others a ios 8.1 issue.
As for Wi-Fi issues another topic but there is certainly problems with slow wifi especially safari disconnecting in ios 8.1 this is a worldwide issue.