Lower the threshold for Low Disk Space warning in Ubuntu

The Low Disk Space warning in Ubuntu is set at 95% and minimum 1 GB free space, which can sometimes be too late if space is running out.
If you would like to get a warning earlier, and more time to clear up space before everything crashes, open dconf
and set these values:
/org/gnome/settings-daemon/plugins/housekeeping/free-percent-notify
"Free percentage notify threshold
Percentage free space threshold for initial warning of low disk space. If the percentage free space drops below this, a warning will be shown."
Decrease from 95% to for example 85%.
/org/gnome/settings-daemon/plugins/housekeeping/free-size-gb-no-notify
"Free space notify threshold
Specify an amount in GB. If the amount of free space is more than this, no warning will be shown."
Increase from 1 GB to for example 30 GB.