I used to check all the time...Like 20 times a day, but it started driving me insane =P Now I check once in the morning and maybe twice in the evening.
once in 2 months. i used to check 3 times a day years before, and now i lost interest since my payments are above $100.
Once or twice per day, if I'm check thrice per day, i will totally becoming insane, as checking it too many times will make me get nerve over it...
twice a day I think is normal, you need to check if somebody been clickbomb your ad so you can let google know
I don't use adsense as often, and don't concentrate on earning with it as much. Therefore, I check it roughly once a month.
funny, i used to check it a lot when i wasn't making much and i had just started. ironically, now that i'm making a decent amount, i only check about once, sometimes twice a day...(if i'm doing some really lame work at my computer and feel like procrastinating i tend to check more frequently)
lol i checking it every minute. I used adsense notifier of mozzilla that's why i can see it every seconds or minutes.