It can be used in various contexts, like:
* Time of day: "Son las tres de la tarde." (It's three o'clock in the afternoon.)
* Duration: "El viaje duró dos horas." (The trip lasted two hours.)
* Weather: "Hace buen tiempo." (The weather is good.)
* Historical period: "En la época romana..." (In Roman times...)
It's a versatile word that can be used in many different ways.