The best extension or program of this kind. It's free and open source and has good performance.

Amazing! I use it to block distracting sites in the morning, so I can get the most out of my morning productivity!

My only regret is that I didn't sign up for this sooner!

Awesome!! Saved my life!!!!!!

Very amazing app. Must install

Bagus

This extension really helps me control my social media addition. Thanks to the author!

Works like a charm, has all the features for free

Справді ефективний додаток, особливо під час екзаменів. В ньому неймовірна кількість різноманітних налаштувань, хоча з ними треба розібратися. Інтерфейс надто простий, але це не відміняє користь від додатку

Saved my finals

it's a vewy good boy. Is clean, does it's job well.

Very useful! Has many options to suit practically every desired blocking conditions. The only big flaw for me is that on Android, it keeps counting the time when the screen is locked or when I don't use Firefox. This is due to Firefox not allowing add-ons to detect that. My workaround is to close the browser when I don't use it. It also saves battery.
I donated to the add-on developer.