Like Jess said, it really depends on quite a few things. I have geckos that will stop when they are full, and I have geckos that COMPLETELY clean their bowls every time I put anything in it, be there 3 worms, or 30. I also have an older adult that I feed only once a week (she's curvy ). It's really up to you, and how much you think they "need".
My first leo was a little like one of leapin's. He/she (debating on a different thread) used to clean his(we'll say he) bowl whatever the amount of worms. A few times exceeding 20. Now he's slowed down a bit, though, still consuming a healthy amount.