I actively log out of them on my main device and use a second device to access them that I like to use substantially less. The device sits next to me every day, and is accessible at any time.

It has substantially reduced my usage.

Enabling a second profile on my android phone and putting Facebook in there instead of in the browser on my primary profile led to an ~90% reduction on the time I spend on Facebook.

However, I do have to check it from time to time for one of my jobs (to monitor our Page and events, and respond to customers), and the occasions when I switch to the second profile can still hook me for 20 minutes of scrolling...