every time I start my pc I first login to adsense as I am new bee and only 1.5 month old so anxious to know about my earnings
2-3 times a day, used to do it more until i've discovered that it's updated just once every 4-6 hours.
I heard from a friend of a friend who has a cousin who's boyfriend works for Google that if you check your stats more than twice a day, they think you may be clicking on your own ads and you're checking to see how much more money you've made. So they put a watch on your site. Obviously just a rumor, but you never know.
I hope not as this lately I have been doing some ads optimization on my site and checking the performance on them every 20 - 40 minutes. It is starting to wear of again now though, as I now realise that I have done the right optimization and CTR has improved on some parts of the site rather well.