Depends on the age of the snake as well. I personally would rather see the little ones taking an appropriate sized small prey item every week. I like that I'm getting a good routine set down with them early in their lives.

With our adults some of them naturally want to eat every week, some of them do seem to do better every couple of weeks. They are still offered the chance to eat every week. They decide for themselves if they are interested or not. As long as overall their monthly total prey volume is appropriate for that size of snake and no single prey item offered is massively too large, then I think it all works out in the end.

As Ed said, these are creatures of habit so whatever feeding routine you use, if it works, stick with it.