How often you check you adsense account should have no bearing on how much adsense earns you.
You earn money through adsense when someone clicks on an ad, so the two activities are unrelated.
I've found that I make different amounts on adsense purely because it earns money from clicks. These click values change in value all the time and so do the number of people clicking my ads. Sometimes I have a great day where lots of people click and other days can suck.