User blog comment:Sannse/Blocking Best Practices/@comment-452-20121010002829

My personal creed with block durations is: block them for only as long as they have been a problem.

So I quite literally only block potential troublemakers for 1 second if they've only made one blockable edit, so that they are entered into the block log for future reference. If they make another blockable edit on the same day, I block for an hour. If they may a blockable edit the next day, I block them for a day, if they make a blockable edit again after a day block, I give them a week block, and so on.

I see a lot of power-tripping admins giving out "1 year" or "infinite" blocks, but there's really no point in having a bunch of active extended blocks for people who weren't going to return anyway.

(All of this assumes that a some form block is needed, and that warning and discussion avenues have not helped)