I recently completed the Hazel Field Guide course, created by David Sparks, and it has been an eye-opener with regard to just how much of the power of Hazel I've not tapped into!
I have a system in place that uses tagging to tell Hazel what to do with various files, but that still meant some manual work to organise things. Now I can use the source of downloaded files to give Hazel a much better idea of what needs doing, saving myself both time and memory (since I'd previously needed to go in and tag the files after downloading.)
The course has also shown me how to work around actions that may take a while to complete, so there's less danger of things stalling.
I've had Hazel installed on my Mac for years, but I'm still learning and improving on how to use it to automate more of my digital life.