When I travel for more than a couple of days I sync my iPhone with my laptop. That way I have a backup copy of my data (photos and notes, mainly) as well as a way to freshen the music and movies a bit.
On my last trip I decided to sync my iPhone in the two hour layover I had in Denver. I had my laptop on one leg and my phone on the other. Once I’d started the transfer my phone promptly fell off my lap and pulled the USB cable out. I plugged it back in to continue but the damage was done. iTunes claimed my phone was mated to another iTunes library, and showed all the data as being the orange-colored “Other” data in the usage graph. It wouldn’t resync with the library, no matter what I told it to do.
“No problem,” I thought. “I’ll just restore the phone.”
I had never restored my iPhone on my laptop, so I didn’t have the firmware. There wasn’t free wireless, and if there had been the firmware is 160 MB, which is a lot for the sketchy connections I seem to get in airports. I ended up sleeping all the way home anyhow, but the moral of the story is:
If you sync your iPhone with your laptop make sure you have the firmware, either by downloading it or by doing a proactive restore.
If you do download the firmware you can shift-click (command-click on a Mac) the “Restore” button in iTunes to select the firmware file.