[Q] Time to buy a new battery? topic

I've really loved my Nexus 4, except the battery life is just awful. I've used different kernels, undervolted, switched to 2G, turned brightness down and everything else you can do with the software to get more out of the battery.

Since I bought it used, I'm thinking maybe the battery is a little old and could use replacing. Is there a way to tell before I waste any money buying another stock battery? Like a sensor on the battery that tells you how healthy the battery is and if it still holds a good charge?

Also, are there any options for extended batteries besides the Mugen extended battery case? It's almost as much as I paid for the phone!

Thanks for any suggestions