I've generally been watering them once a week, but I like how you described dry, because I'm not sure sometimes whether it's truly dry or not.

We live in an apartment where there's really no good place to put it outside.

The pot has draining holes, and its never sitting in a puddle of water (I actually set it up to sit on a 2-foot high iron grid-like platform with a pan on the floor to catch any drippings.)

Interesting note: Lately most of the yellow spots have been fading to green like the rest of the leaf.