I've had my iPhone 3G for about a year now, and it seems like at least once a month, it gets bogged down and gets slower and slower - horrible lag when typing, going back to the home screen or opening an app can take 20 seconds.

Has anyone else run into this and found "the" solution. What you always read on other boards is to reboot the handset (hold down home and the power button), but that doesn't improve anything for me.

I've reinstalled the OS like 5 times now, and I'm getting pretty sick of doing it so often. And I don't buy that it's a hardware issue really, since it works fine for weeks after a fresh install.

Anyone have a solution or an idea of what specific actions cause this kind of evident data corruption (OS corruption?) and slowness?

Note - I'm looking for specific things here. That is, has anyone done the research to see exactly what on the phone operating system is getting messed up that causes this lag (which is discussed all over the internet, with no working solutions). I don't own a mac, so I can't delve into the guts of the iPhone very well to see what's up with it...

Some additional info:

1. Reboots (hold down power/home) and "Sleeps" (slide off) do nothing. Only fresh re-installs help
2. I only have about 15 apps installed - sometimes you see the answer to uninstall apps if you have too many, I'd hope that 15 isn't too many, and even when I've had none installed, it still gets hung up after a period of time.
3. This phone is not jailbroken, and it is running the 3.0.1 release.