Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Why would it damage the iPhone?

I seldom do one, though. (Are we really talking about a hard reset, though? where you hold the on-off switch and the home button until the white Apple logo shows up and the phone restarts?)
 
nope doesn't damage the phone at all! i do it every time i install a significant application, it's actually RECOMMENDED, think of it as restarting your computer, doesn't do any damage
 
Wirelessly posted (iPhone: Mozilla/5.0 (iPhone; U; CPU iPhone OS 2_2_1 like Mac OS X; en-us) AppleWebKit/525.18.1 (KHTML, like Gecko) Version/3.1.1 Mobile/5H11 Safari/525.20)

As many times as needed.

Even though you did not ask for additional input I plan on addind my 2 cents worth anyway. So here it goes:
It could potentially corrupt something in the phone since it is sort of like killing the power to a computer but it shouldn't do any permanent damage. Since you are doing it 3-4 times a day I would suggest doing a software restore on it. I rarely have to soft reset mine since the last firmware update.
 
What's the difference between a soft reset and just shutting it down and restarting it?

I understand that you might be forced to do a soft reset if the phone is hung, but other than that what's the difference?
 
Actually, power-cycling a machine frequently will indeed shorten its life.

SOURCE: UN Study

Much electricity is wasted as computers also tend to be left on when not in use, even overnight. Many users falsely believe that turning off machines can harm the components. In practice, turning computers on and off shortens their lifespan only after around 20 years of use, not relevant for most equipment.
 
Yep. It does affect component lifespan. Power-cycling refers to on-off-on cycling, rather than just using the on/off toggle in a normal manner. While both will shorten the lifespan of the components, the former is a lot more damaging than the latter. Still, most modern components have fairly long lifespans, so this isn't a huge issue for consumer hardware.

It's more of an issue when dealing with server hardware (which does *not* react well to power-cycling).

Risk of component damage is not the reason I'd recommend against resetting your iPhone though. While it's certainly the only logical step in the event of a freeze or panic, it doesn't make much sense to do it instead of just halting the OS normally. Resetting it might interrupt writes, and while it's probably not going to be fatal to interrupt a write (HFS+ is pretty resilient), it's not a good idea unless it's necessary. You only save a second or two over a normal shutdown anyways, so resetting the iPhone after an install (as opposed to restarting it) seems kind of silly to me...
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.