battery life is battery life, phones dont last forever, but each and every phone has its own limit.
I've had my Nexus since November 16th, and from Nov 16 till December 31st I didnt do anything to it but leave it stock. Back then I had amazing battery life, I mean when I use my N4 it gets me from 7:00AM in the morning till 3:30PM in the afternoon (8.5 hours) with about 15% left. Now, I use my phone ALOT, always on Auto Brightness, using 3G Data (no 4g on Windmobile :'/), streaming music from Songza, reading androidcentral, reading news using flipboard, typing notes in class using evernote, taking pictures of the textbook for that nights homework. So you can see, if you do all this or more, your battery life will probably be crappy. But most people are not like me, most people just use their phone for simple twitter, instagram, facebook, occasional youtube videos, and they're mostly always on WIFI, and they have an ipod or download music to their device. So with my friend who is just like this, he gets battery life from 6:00AM in the morning ALLLLLLLLLLL the way until 1:00AM the next day... and he still has 37% left!!!!!!!!!!!!!!!!!!!!!!!!! Which is utterly insane!!!
So there you have it, battery life will vary.
Now, after December 31st, I rooted my phone and am using Paranoid Android with the help of Antutu Battery Saver and CPU Master, with these two brilliant apps I can get battery life from 7:00AM till 3:30PM with about 42% LEFT over!!! Which is amazing because I used to be almost dead right before I walked into the house, so there are multiple ways of achieving good battery life.
Now I'll give you a tip, when your phone gets hot and it makes you sweat, STOP USING it, when a phone is hot it uses battery WAY MORE QUICKLY, I played Flappy Bird for 12 minutes, started at 78%, went down to 65%.... auto brightness. Then I played QuizUp from 63%, went down to 52% in 8 minutes. 8 DAMN MINUTES. I played both of these with no other apps running, so you can see gaming, or hot phone = bad life