It all depends what you do on your phone. If you are browsing the web via 3G or any apps that requires network, but using 3G then most likely it will use your battery a lot. You can save battery life by turning on wi-fi when you are using it. Games can drain battery depending on what games they are. Games like Infinity Blade, FIFA 12, Real Racing 2, or any games that requires lots of power will drain battery. When playing this games, I would suggest playing them while you are charging them.
I usually charge my phone every night when I go to sleep and unplug it when I go to school. Mostly around 6 PM, my battery is usually around 70%-60% depending on what I do with the phone. When I plug my phone to charge, it's usually around 40%.
As for my notifications, they are turn on, but I have turned off the view in lock screen because notifications will trigger the lock screen to turn on and that can drain the battery, I have it set for Banner view so when I unlock the screen then I get the banners, which saved me a lot of battery life in the past. *The only apps that I have set to view in lock screen is the SMS apps, and phone calls.
Average usage that one would get is usually around 4 hours to 6 hours of Usage (not Standby time). Standby time doesn't really matter because Standby time starts ticking when you unplugged your phone until you plug it back in. However, if both usage time and Standby time is the same then that means something is running in the background when you are not using the phone.