I could honestly go 2 days with heavy heavy use without even plugging it in. ;-) That is why I will never buy a Samshit phone until they start putting better quality longer life batteries in their phones.
Just bought a gs3 for a really great price off contract and am anxious to start using and trying it out. It's still pretty much a brand new phone in my opinion. It just came it in April. Only 6 months ago barely. I don't see how people can get a new phone every year or less. The technology on this s3 is still top quality. Now I can finally use android and iOS together when I need to. I'm happy with getting a phone a few months after its been released so as to know what it can do and allow the bugs to have been hopefully worked out of them. And if I need to I can probably sell this s3 for more than I bought it for I'm sure.