Extending Battery Life (iPhone)?

All my family members tell me that in order to save battery life on the iPhone 4S, you must close all running apps-you can do this by double-tapping the home screen, tap the app, when they start to jiggle, you push the "-" and they will stop running).

Is this necessary for conserving battery life?
I know this is just one way to conserve battery life, but is it at all worth it?

Yeah that does help a lot of the apps aren't minimizing properly.

Some other stuff:

-Turn the brightness down as low as you can tolerate.
-Make sure bluetooth is turned off.
-Go to settings > mail > push… Turn off push and select "fetch" for 15 mins, 30 mins, 1 hour, or manual. What this does it only searches for mails at specific intervals (or when you click the app) instead of constantly searching. This can save the battery life.

Probably, try it for a day to see if you save battery. If you want to save more battery, then dim the screen. Go to settings > brightness & wallpapers.

A better solution to constant app management which is so time consuming or reducing your brightness which lowers visibility is to get an external battery case. You can get one that hugs your phone just like an otterbox or other phone case. Some popular brands for this are Mophie and Energizer. They can get expensive, but look for a coupon and you can usually get one for a good deal.