Backup battery or not?

That is the wrong question. Of course you need a backup battery for your camera. How many times do you find yourself out of battery during a shoot? Me, a couple of times, just enough it looked like I was not learning my lesson.

I did buy a backup EN-EL3e battery in the summer. It saved me on multiple occassions thereafter -- I tend to shoot over 300 pictures in a single day. So, why am I writing about backup batteries? It is obvious enough you need a backup battery, yes? But, do you know you should not go cheap on backup batteries? After having used two no-name brands made in China (one for my Canon PowerShot SD110 compact camera, and another for my Nikon D80) I would say, stay away from them. They may be cheap but after maybe 10 charge cycles, they break down. My EN-EL3e backup battery is dead after less than 10 charge cycles.

I am not going to purchase another EN-EL3e battery as I have a battery grip with a built-in battery, in addition to the original Nikon EN-EL3e battery. I will wait to see how long the battery grip will last, although I have a feeling that it is no longer pulling the weight that was advertised. It is supposed to store 2.5x as much charge as the normal EN-EL3e battery, so effectively, you should be able to take 2.5x times as many photos. My observation thus far has been purely qualitative. I am starting a quantitative measurement now.