How did early, e.g. ancient to early medieval times, people have a sense of time, i.e. an hour, with no clocks around?
I am aware that mechanisms for time measurement existed, sundials, water clocks, candle clocks, etc., but I assume they were not affordable to everyone. Therefore, my question is directed primarily towards common people. As an example, consider a number of guardsmen assigned to a relatively isolated watchtower, who are assigned to watch shifts. I imagine that by day they could orient themselves by the sun, by night they could use the moon and stars, but what when there are no celestial objects to reference? Furthermore, this approach fails to take into account the variability of celestial movements due to the change of seasons. Finally, the concept of an "hour" is very old, ancient civilizations divided the day for sunrise to sunset into 12 parts, how does one intuitively divide such a large timespan into units, which are rather large by themselves? Was some "chief" assigned the duty to anounce/keep track of time? It appears logical to me that the passage of time was not so crucial to people then as it is now, but I'm baffled by the huge impact of relativity in my above considerations, assuming they are at least partially correct, of course. Imagine what an hour would feel like to a worker in the fields and to his overseer and how the day would be divided if either of them were prompted to announce the passage of one hour.