As a developer, this means the only time many users will "restart" the app is when they update, and the restart is forced upon them. So make sure your apps are stable!
I've never ever ever pressed that little red (-) icon. On pretty rare occasion, I need to hold power and then hold home to kill an unresponsive app. But I've never "quit" an app when I was done with it. I've had an iPhone since the beginning and my battery life and performance has always been stellar. Only apps that passively use GPS have been a problem , so I uninstall those.
This is also (mostly) true on my Mac as well. I leave DOZENS of apps running and only kill them if they start sucking down CPU cycles. Generally, most apps sit there, do nothing, and get paged out to the flash disk.
I'm also a little annoyed each time I meet a non-techie who had some techie tell them "Oh, here's how you close apps. It will make your phone faster." Try as I might, I can't convince my girlfriend that it has absolutely no effect. She religiously closes every single app in that little tray once or twice a day.
It's 2013 people. We don't (shouldn't?) need to manually manage memory for our computers.
It shouldn't be that way, but it is, and the only way I have to control it is to go manually quit certain applications when I'm done with them.
Do you have any evidence of this? Have you run a controlled experiment? Because that makes zero sense. I'm 99% sure that you've been conditioned to press a placebo button.
To answer your question though, yes, I have experimented several times over the nearly three years I've owned the phone (plain old iPhone 4 from sept 2010). From a full charge, airplane mode on (turn off the RF drain and minimize outside events -- namely texts and phone calls that I cannot control), phone set to sleep after 1 minute, screen brightness minimum, and with nothing else running, I can start the camera app (pre-configured to be in still photo mode, with flash set to "off"), hit the home button to drop the camera app to the "background", start and then quit the notes app to make sure the last thing I did was something other than the camera app, and doing nothing else with the phone -- lay it on the coffee table and literally do not touch it -- will drain the battery in about 3 hours, 4 max. Doing the same routine, but quitting the camera app, then starting and quitting the notes app and I can leave the phone on the coffee table for days (although I usually give up after about three and start using the phone again).
Everything else I can (and do) leave running with no ill effect.
Bug in the OS? Bug in the built in camera app? Something defective in my battery/phone? Perhaps -- I don't know, and don't really care. I just make a point to turn the camera app off when I'm done with it. Since I usually have a DSLR with me, I rarely reach for my phone for photos in the first place, so it simply isn't that big of an issue.
OK, I lied. The only other time I close an app… The. Chess.com app's analysis board becomes unbearably sluggish if the app has been running too long.
Both instances can be pinned on the app rather than iOS.
I'd say most techies also don't close out their apps. I certainly don't.
-- Steve Jobs iOS 4 introduction http://www.pcworld.com/article/193590/liveupdate.html
You don't need to do that to save battery life. Trust the iPhone. -- Steve Jobs email http://www.johnsphones.com/all-articles/steve-jobs-trust-the...