This is probably a clear metric for our annoying friends who complain that they don’t get high enough quality sleep, but go to bed at 2 and have an alarm set for 7 every day. Sure you may have worked best on 5 hours sleep in college (though probably not), but if you aren’t "feeling well rested after waking up at least five days a week", you might try more sleep.

Some people need this advice, and a clear metric to hit. I’ve known them, and although I failed to make a dent, eventually something did. Maybe it was an article like this.