With worms, I find my snakes prefer several small feedings a week. Mice will hold adult snakes for about a week, but they still like a worm snack mid week if they can get it. (They do beg!)

I feed until they are full, or I see a visible bulge in their middles. If they are constantly piggy, watch out for signs of obesity and start limiting food. My snakes self regulate well on worms and fish, but will start to get fat on rodents if I let them.