I've got 4 spare batteries for my N3. I bought them in a package deal with a cradle and charger I believe. They do not allow NFC, but they work well. Honestly, I have never needed to use them - I bought them with the cradle (which I quit using, lol). But I sometimes do extended backcountry hikes and use my phone and several topo mapping/gps apps for keeping track of where I am, and therefore like to have the security of extra batteries. But most of the places I do these hikes has no cell service, so when I put it into airplane mode the phone literally last days on one charge, even when using GPS, playing music on the phone, etc. Which means the cell radio does take up a lot of battery when in use. In any case, I have been extremely happy with the battery life on both my N2 and N3 and expect the N4 to have similar, if not better battery life. And I will still likely buy a couple of spare batteries anyway, lol.