Depends on the era, location, and vocation.

The idea of showing up “on time” generally came with clocks. Prior to that there were really only a few defined times in a day for most people - sunrise, noon, sunset. So, you learned to milk the cows when they needed it and got used to the sleep cycle that facilitated that. Similarly, you opened your shop when you needed to in order to serve your customers. Schools might begin “about an hour after sunrise.”

However, if you REALLY needed to be up early (like attacking an enemy camp before dawn) you had two choices - have the night guard wake you (night shifts could be tracked by the stars) or drink a LOT of water before bed. First person to wake up to take a leak kicked everyone else awake too.

Then there is the old trick of having an annoying animal around that wants food in the morning or who makes a lot of noise like a rooster. Also, in cities there were people who would wake you up for a fee by knocking on your window (they stayed up all night and slept during the day and relied on astronomical observation or used a time counting device like an hour glass). This practice of having someone knock on your window to wake you up continued into the early era of clocks when not everyone could afford a watch or clock.

Businesses and churches also helped announce the time with bells and whistles that could be heard from far away. People got used to hearing the church bells calling them to service or the whistle announcing the beginning of a work shift.

That being said, ships and similar operations had hour glasses and also took note of twilight times. As long as someone turned the glass, then they knew what hour it was. The glass could be calibrated at noon or midnight. Water clocks and other devices were also used in wealthy households, military operations, churches, and larger cities.

In rural areas though, having a clock just was not a big need. Animals and children know when they want to be fed and they know how to make their desires known.

The thing to remember is that our sleep schedules are so compromised in the modern world that we have very little comprehension of normal sleep cycles and modern technology distracts us from the passage of time. I once spent about six weeks in a cabin in Montana without a clock, watch, television, or radio. I was pretty surprised at the end to realize I had been getting up around 4:00 am and going to bed around 7:00. Once your body resynchronizes to more natural rhythms it’s not too difficult to get up the same time every day with the birds, eat breakfast, leave the cabin when the deer move past on their way up from the lake, eat when the sun is high in the sky, and go to bed when the light starts to fade. We naturally comprehend time and can sense it. We just tend to forget that in a world of glowing screens with clocks shown everywhere.