Example cron task for auto-removing old downloads on macOS Big Sur and Catalina

crontab

# Cron on modern macOS systems (10.14+) requires Full Disk Access permissions
# in System Preferences->Privacy & Security. To enable this, drag the cron 
# binary from /usr/sbin/cron into the Full Disk Access list. 
# More here: https://apple.stackexchange.com/a/372810/42898
# https://gist.github.com/joemaller/c4c0a6000ac53c8b1a70ff66c547380a

# Removes downloads older than 14 days. Runs every 6 hours
45	*/6	*	*	*	echo "$(date)\nRemoving downloads older than 14 days (cron)" >> /tmp/cron.log
45	*/6	*	*	*	find ~/Downloads -maxdepth 1 -mtime +14 -exec du -sh {} \+ | sort -rh >> /tmp/cron.log
46	*/6	*	*	*	find ~/Downloads -maxdepth 1 -mtime +14 -exec rm -rf {} \; >> /tmp/cron.log 2>&1