i think a lot about how it's hard to assess maintainability of work conditions because you're often burning down the burnout clock instead of building it up.
think about trying to assess your gas mileage while you're driving on the highway. you've got an MPG readout on your dash. you can always get the MPG to increase by letting your foot off the gas a bit, but when you do that, you're eating into your overall velocity and eventually you'll just stop.