If we could not tell time there would be no such things as seconds, minutes, and hours. If we didn't have things such as watches and clocks, we would have to adapt to learning how to tell time by using the sun. If we had to use the sun in order to tell time, it would not be the exact time, it would be estimations on time.
Without time we wouldn't really have the need to be anywhere at a certain exact time. Without an accurate way to tell the time we cannot exactly give an actual time.