I clean my tank about once a week, a good full clean...removing everything, washing the water dish, wiping tank with Lysol wipes, letting it air out, then putting new paper towels in and then replacing everything.
Call it overkill but ever since I had mites a few months ago, I'm a bit paranoid about making sure there isn't anywhere those suckers can hide or survive.
Thats why I don't like aspen, I don't like the idea of spot cleaning. I like to make sure the tank is thoroughly clean and with aspen thats not really possible.