I don't think it lasts for months but it does last a long time. An example. A week ago I had a 90% charged battery and my girlfriend and I went taking pictures (she using my V1). We took pictures for an hour or so, her using the LCD preview (which burns battery pretty quickly). I looked at the battery this morning and it's at 81%. I've found that it drains overall pretty slowly. I've seen it go a couple of weeks and still have some charge left. The power draw is minimal when not on so it's more about how long the EN-EL15 holds charge when inactive.