This just seems like one of those things that most people go on because of conventional wisdom, which stated above makes for one prey item per week. But I think it is a valuable question to ask because questioning conventional can be good at times (I mean questioning, not flying in the face of it I also follow the same pattern). Maybe because they gain a reputation as finicky eaters it could be possible that some snakes don't have a metabolism to justify a weekly meal. When it comes to some balls (mine cough cough) all you can do is offer the option once a week. But when they take the prey, oh what a week! Seriously, I can't think of anything more gratifying than my balls eating.... (hehehehe)