I'm in the process of switching from Chrome to Firefox for ethical/privacy reasons. On Chrome I really rely on an extension called Strict Workflow that combines a Pomodoro timer with website blocking, but I couldn't find a similar add-on for Firefox. Instead, I combined Leechblock's lockdown feature with a pomodoro add-on called Tomato Clock. When Tomato tells me I have a break, I just enter my password to override the lockdown for 5 minutes and get back to work. So far it's working great. Thanks guys