I have Ubuntu installed on a small partition (20 GB), so my disk space is at quite a premium. I constantly have to clear out old linux-header-* and linux-image-* packages, because they consume relatively large amounts of storage for each version (~270 MB), which really adds up when there's like 20 of them installed.
There are times when apt-get autoremove gets rid of a few of them, but it still leaves a substantial amount behind.