My Voyage losing battery power?

Hello good people,

I have had my Voyage since it first came out (wifi + 3G). Love everything about it. However I am noticing that the battery is going down faster than it used to. Is that possible? Other than a few very shiny pixels in a couple of places, I am otherwise still happy with it.

Is it better to replace the battery (and where does one find it)? Or is it better to find an old Voyage? I don't feel yet like upgrading to a Paperwhite but that might be the best solution.

Grateful for any thoughts!

k4k