I say go with what you feel. Sometimes I take a random break in the middle of the week, other times I go 7 days in a row. Think frequency, intensity, time, type. Apply that to you workout plan and you will be able to answer many of your own questions.
"Most men stop when they begin to tire. Good men go until they think they will collapse. But the VERY BEST men know that the mind tires before the body and push themselves beyond all limits. Only when all of these limits have been shattered can the unattainable be reached." ~Dan Gable