With full blocking I used to cheat by disabling the block, and then "forgot" to enable it again.
With delay-based blocking I'm also cheating: instead of waiting for the delay I get up and do some minor chore. I used to feel smug about how clever I was, sabotaging my own block. Until I realized what a positive change this was.
PS: I've waited 40s to submit this comment. You'll need another plugin to recover the text if you submit and then hit the delay page. Or submit before the timer runs out.
Link to the extension which in turn links to the git repo: https://addons.mozilla.org/en-US/firefox/addon/delaywebpage/
But the block repeats every few hours, and I'm pretty sure that clicking on a link within the same tab repeats the block then (maybe depends on the page). So yes, the "dosage" of how many delays you get is not very well controlled for. Still, I'm using this setup for years and it definitely does something for me.