click on your username on the top right corner. There is a dropdown labeled "noprocrast", and I think the text-fields under it saying "maxvisit" and "minaway" p

click on your username on the top right corner. There is a dropdown labeled "noprocrast", and I think the text-fields under it saying "maxvisit" and "minaway" put, respectively, a maximum amount of time that it will let you use the site contiguously (in minutes) (or, possibly, maximum number of distinct times it lets you use the site per day? not sure) and a minimum amount of time between visits. I haven't used the feature, so I'm not sure quite what it does.