For those not aware, HN has an anti-procrastination feature in the account settings called "noprocrast". If you turn it on, when you visit HN, it only lets you interact with the site for the next "maxvisit" minutes, and the limit only resets after "minaway" minutes.<p>E.g. if you set "maxvisit" to 60, set "minaway" to 720, and access HN at 4 PM, you can use the site until 5 PM, at which point it locks you out for the following 12 hours.<p>I've found that this is an <i>excellent</i> anti-procrastination measure. It takes what is usually an impulsive decision ("I'm just going to check this website real quick") and turns it into a conscious choice ("Do I want to start my one daily HN session right now?"). Rather than impulsively taking 5 minutes here and there, I have to take my time on this site all at once, so I only come here if I think it's going to be an actively good use of my time.<p>The problem is, this seems to be rare among productivity apps and "screen time" features. Most of them do something different, such as:<p>- Time limits for apps that only count time when you have them foregrounded<p>This doesn't work as well, because "a half hour" on a particular app can easily cost you more than a half hour of productivity if you split it up. Every 5-minute session distracts you from what you were doing before.<p>- Scheduled or ad-hoc downtimes for apps<p>These tend to be really inflexible, and my time isn't this well-planned. Both this and the previous feature just train you to hit the "Ignore limits for the next X minutes" button.<p>- "Screen time reports" telling you how much you've been using an app<p>This feels more like a guilt trip than an actual anti-procrastination measure. You know where your time has gone, but not how to fix it.<p>So are there any website and app blockers that actually take this strategy, letting you ad-hoc allocate contiguous blocks of time to access apps or websites, then locking you out for a while after that time is up?