On one installation of Ubuntu 12.10, I was surprised when I ran out of room on the root partition. The solution was easy, however.
When I installed Ubuntu 12.10, I overrode the installer’s ridiculous Windowsesque everything-goes-in-one-big-partition scheme, and instead manually set up a more robust partition scheme of root, home, and swap. I wasn’t going to go on an install fest, so root got a reasonable 8 GB and I didn’t bother with babysitting the disk space usage.
Good thing I did, too, because after a few months’ use I was surprised to get a warning that the root partition was 99% full. Huh? A little investigation revealed that over a dozen older kernels had accumulated as newer kernels were installed. A quick search in Synaptic for linux-headers and linux-image found them. The newest kernel was working fine for me, so I performed a full uninstallation of all older header and image files. That solved the immediate problem, leaving the root partition only half full.
In the future, whenever I install a new kernel on that box I will leave only the immediately preceding known good kernel installed. All prior kernels will be uninstalled, being no longer needed. And when I install Linux on a box I won’t be using myself on a day-to-day basis, I’ll give the root partition more room, perhaps 15 GB.