Complete overkill, but my router enforces a daily limit for sites I visit too often. It's not that difficult to set up. Make a iptables chain, route all traffic

Complete overkill, but my router enforces a daily limit for sites I visit too often. It's not that difficult to set up. Make a iptables chain, route all traffic that matches certain ips to that chain, add a --limit and --limit-burst counter to that chain, deny by default, allow when below said limit. For bonus points, make all http connections redirect to your favorite todo list when you've exceeded your limit, and deny all ssh access (to the router) during working hours. Setting it up was complete procrastination of course, but it works better than any manual block list. By slightly lowering my daily time waste allowance I can reduce the time I spend on sites like these. EDIT: Blocking with hosts is terrible, because you don't want to block sites permanently, and if you continually enable/disable the block list your muscle memory will unblock a site even before you realize you should be working. Cron job limits don't work when you don't have very strict working hours. Basically, you want to take a break for a few minutes every hour or so, and you need soft limits to enforce that.