Too much humidity is NOT your friend. I spray lightly all over the surface of the box, eggs included, about once every 2 weeks. But that is what works for me, with my house humidity level and such. Each setup is going to have different parameters. I use plastic shoe boxes with "Press and Seal" for a lid, with toothpick holes in the top for venting. I cover all of the boxes with towels to cut out light and keep them on a plastic shelf that is out of the way so it won't get bumped, and out of the light. I check each box visually once a week to be sure there is nothing funky going on, but no more than that. I know my particular variety (panthers) take around 9 months +/- 1 for me, so when a clutch gets closer, I up the checks to every 3 days, looking for windowing and/or sweating as indicators.
But as I said, that's what works for me. Ask a dozen people and you will probably get a dozen different methods.