Used Iphone 4S: How long should the battery last?

If you're trying to gauge the batteries health, generally speaking, I'd like to know your opinions on two things:

1) How long SHOULD a full charge last if it the phone is ON, yet is not put to use at all. Meaning no calls made nor accepted and no anything else. No pictures, game playing, nothing.

2) How long SHOULD it last if used from time to time to make calls and browse the internet.

If the iPhone is in standby mode it should easily last a day and a half

If it's used from time to time to make calls and browse the internet expect no more than a day's worth of usage because it is a personal computer after all not just a cell phone