Service/daemon for surveilling size of folder

Sometimes a folder gets filled up with junk. The web browser’s temp and download folder, Visual studios test run results folder etc.

Why not have a service or daemon to surveil this folder and erase old files when it gets over a certain size?

The Visual studio test run results folder could be emptied a day after the test runs (YMMV). The web browser download folder could be set to erase files older than 30 days or so while keeping the large files since they probably took a while to download. The surveilling application could send an email or enter an entry to the event log instead of erasing.

An other use can be for all the log files, one per day, on a web server. Why not send each file to another disc at the end of the day?