I am an engineer. I am a nerd. I buy lots of gadgets. I buy their accesories. I drain and charge a lot of those gadgets a lot. I have tried to save a buck here and there in the process, but it hasn't worked out well when it comes to batteries. It is always a good idea to buy backup batteries for your camera, cell phone, video equipment and other devices that see a lot of use away from the home. BUT BUY THE OEM replacements. Read all the way through to BIG WARNING section below.

The problem is, not all batteries are created equally. To keep it simple, the high quality OEMs like Sony, Panasonic, Olympus, Nokia, Samsung, etc. go through a lot of research and development to meet requirements and to stay competitive with the rival brands. Buy the REAL ITEM! I even purchased a Maxell brand battery once for my Sony camera. It was OK, but the Sony battery lasts much longer... almost twice as long. So I hardly ever use the Maxell. It is just a back up.

BIG WARNING: There are MANY counterfeit OEM looking batteries out there, so be VERY careful of what you are buying. USE EBAY's RATING SYSTEM when you wonder what you might be getting. I was careful to make sure a Nokia battery I was buying was the real deal. I bought it, and when I got it, it was slightly different that my original. It was a fake. Problem - The seller only had a few reviews. Now, a few years later, that seller has a bunch of low approval ratings. So, When it comes to this type of item, trust only the sellers with a high quantity of ratings and a high percentage. The others may be legit, but there's no way to tell unless they have the numbers to prove it.

Good Luck and please mark my guide as helpful if it was.