I just recently ran out of space on my relatively new OSX desktop machine, which came with over a 1TB.
Strange! I thought.
Downloaded the excellent (and free) OmniDiskSweeper and let it run.
Well, that would explain it. Nearly 1 TB of core files in /cores.
Removed them and set the hard limit to prevent their creation.
And suddenly I have a very much happier machine :)