It depends on my work pensum and the level of concentration I need for my work, but usually I'm checking the site (at least hourly / every two hours) between

>0700UTC - 1700UTC (core time)

and between  (not every day)  
>2100UTC - 2300UTC

"Session length" between 2 to 10 minutes depending on how much time is at my disposal (I spend more time during my lunch break at ~ 1330UTC.)

Obviously, I don't maintain that rhythm when I'm not in the office or at home – which is maybe once or twice in two weeks.

Related answer [here on Meta SF][1].


  [1]: http://meta.serverfault.com/a/2360/45