As i'm getting a new mobile phone very soon which i have ordered, i have been reading reviews that the battery does not last long even though it says 200 hrs on standby

Been hearing about people charging the phone after only a day or so

The current iOS (5.0.1) did sort (some) of the problems people had with iOS 5.0.

Also depends on your usage, of course.

I charge mine every other day, same as with my previous iPhones.

I think most people need to charge their smartphones every day. If you're browsing the internet, updating Facebook and Twitter, having email pushed to the phone, listening to music, playing games etc, the battery is going to drain pretty quickly.

The latest iOS never did fix the battery drain completely. My 4S can use up to 70% of battery life in a 12 hour period, this is with little use. The phone will not last a day without charging.

This is the second 4S that I have as I took my original 4S back to Apple within 7 days after launch day again due to the poor battery life. It doesn't look like its hardware but a software problem.

It's all down to how you use it. The true killer is the LCD screen/brightness. Of course, the more you use it, the more juice it needs to power the screen.

On an inactive day, it will only use 20%. An active day, 50 - 70%.

I'd recommend doing the following things:
[LIST][*]Keep bluetooth off as much as you can[*]Keep the brightness down to the point where it doesn't strain your eyes (turn auto-brightness off)[*]Make sure very few services use location tracking (GPS can suck up battery in no time!)[*]Ensure as much of your e-mail/cloud services are push rather than pull (Exchange, iCloud, G-Mail? services are all push)[*]Don't always keep charging the phone every night (especially if your usage is above 50% from the start of the day - maybe buy a 2nd charger for work)[/LIST]