Cadence is a peculiar subject because there are so many different right answers. Pushing the cadence beyond your normal range is more tiring and less efficient, but consistent training at a given cadence ameliorates that and the higher cadence becomes desirable for other reasons.

Personally I do as 10 Wheels suggested, just ride at the natural cadence. Until I want to train at a higher cadence for some reason, which does happen. Sorry if that's more vague than you wanted, but it's my best take on the question.