Fig. time is very important. (Used especially in situations where time is very limited.) Doctor, please try to get here quickly. Every minute counts.When you take a test, you must work rapidly because every minute counts.When you're trying to meet a deadline, every moment counts.
Also, every moment counts. Time is of the essence. For example, Hurry up with those tools-every minute counts, or In performing surgery every moment counts. This idiom uses count in the sense of "to enter into the reckoning" (and hence be important).