Watch for changes in files:

sudo apt-get install inotify-tools

inotifywait -e modify,create,delete,move -r -m /path/to/watch

To do something with the result, the following could be used

inotifywait -e modify,create,delete,move -r -m | while read line; do something_with $line; done 

According to the documentation for inotifywatch, the default limit is 8192 watch descriptors, and you can increase it by writing the new value to /proc/sys/fs/inotify/max_user_watches. On Linux Mint 22 with Surface Kernel, this appears to be set to 29301.

Watch for dconf changes:

dconf watch /