For whatever reason, even if my Macbook Pro computer booted with more than 10 GB disk space available, after working on it and having it powered on constantly for a day or two, its disk space very often will fall dramatically and sometimes even almost fill up with nominally something like 200 MB left. And it often causes issues:

• Having to "manually" kill applications that are no longer responsive using Activity Monitor.

• Some applications not properly exiting and saving status and metadata. For example, Eclipse workspace data, backup files in Emacs, and currently opened tabs in Google Chrome.

I made a Bash script to check and warn about low disk space and have it run periodically as a cron job.