This one really annoys me, as it appears to happen for no reason. Here’s a few tips that I’ve picked up after just about 6 months use:
- Use ‘Restore to Factory Settings’ often – This is a clean sweep of your iPhone and helps it trim down on the trash it accumulates (an Apple product?! trash?! – unbelievable ;-)). I try to do it monthly and am always glad I do. I try and not use the backup that I’ve just discarded too, this kind of defeats the object.
- Clear Crash Reporter – Googled this a wee bit, and I found a few forum entries saying that every time your phone crashes, it saves a bit of data about the issue to the phone, which it then syncs to your hard drive and when you’re syncing and have an active Internet Connection, it’s sending this updated info to Apple, meaning you have to wait for this to transfer. Not good times. My folder had 63 files/folders in it(including a folder called, rather worringly, ‘Panics’)
Here’s a quick preview of my folder,

To clear it, navigate to the following path
\Library\Logs\CrashReporter\
Then delete anything under the directory ‘MobileDevice’
- Consider changing your backup preferences – When you sync, by default, you backup too, if this is not desirable, here’s a link to change the way you manage the data (just don’t cry when you lose something important!)
- Leave some free space! – This one is really important. Your iPhone doesn’t really like being full to the brim (just like your standard hard drive, it’s a good plan to have a portion of it permanently free). So give it a break, and trim down your Music and Photos. I use Smart Playlists with specified max sizes to make sure I don’t put too much stuff on there (eg. Only 2 Gigabytes of music I haven’t listened to yet, ordered by date OR only allow files of under 10 mb into this playlist to prevent the long ‘secret track album closers’) Old Applications can go too, I think this’ll help your sanity too when you see how much neater you can make your iPhone OS GUI (Am I the only one who needs to keep his apps in multiples of 4? :-| – “Hi, my name’s Simon, and I’m a Nerd with OCD”)
Aside from that, I can only recommend you update to the latest version of the software frequently (though iTunes handles this pretty well for you).
Please comment if you know of any other genius tips to help other iPhone users stuck inside whilst their git of a phone works some shizzle out!