¿Es común en español decir el tiempo aproximado? Como en inglés, por ejemplo, algunos digan "Son las dos" cuando son las dos menos diez. O ¿es más común decir el tiempo exacto?

Too easy.
VOTE NOT TRUMP.

Easy for you to say.

get a watch

I think it is something that have changed in Spanish, the same way as it has changed in English over the past 200 years.

200 year ago only rich people had a good clock. Most had only a sundial (a sun clock) and that do not tell the time with much precision. That is why churches have those big noisy bells they ring when it is time to go to church, else most people would not have known, and people would come too early or too late.

Today that is not really needed, Everyone have a good wristwatch, or else a clock in their mobile phone. But churches still ring their bells. Is is a tradition that many would miss if it did not happen.

But because we have good clocks now we tell the time with more precision. 02:45 PM or whatever the clock tell us.  In Spanish or English or Danish or wherever  else good clocks have become a cheap thing. It became that way because clocks became so much cheaper.

regards JakobA