Calling in your primary vs. "Crew savers"

[Rooster]

This coming season will be my first as a varsity official; I got moved up over the off-season (*bows elegantly). One of the truisms I've been told is to make sure I stay in my primary and let my partner take the heat if he passes on a call. I've also been told that crew savers become even more important at this level. So I'm looking for the wisdom of the group about differentiating between "letting your partner twist" and coming to get one that "has to be gotten." I know that game situations will have a lot to do with it, and that there are two schools of thought: Some say get the call right, politics be damned and others say "He or she is a big boy or girl and can take care of him or herself." I'm hoping to form some guidelines based on you folks' experiences. I don't want to step on toes.