Learn Spanish (Latin America): ¿Debería explicarle lo de desocupar el departamento temprano? - Should I explain the matter of vacating the apartment early to him?

Using the conditional debería (should I) instead of the present debo (must I / do I have to) softens the question. It frames your sentence as asking for advice or an opinion rather than asking about a strict obligation. This is a very common way to sound more polite and less demanding in Spanish.

How does the phrase lo de work in this sentence?

Lo de translates roughly to "the matter of," "the thing about," or "that business with." Here, lo de desocupar means "the matter of vacating." You can use lo de + [noun or infinitive] to casually bring up a topic or situation that the person you are talking to already knows about.

Why is the verb desocupar in the infinitive when the English translation uses the "-ing" word "vacating"?

In Spanish, whenever a verb directly follows a preposition like de, it must be in the infinitive form (desocupar). While English uses the gerund ("-ing" form) after prepositions, Spanish always uses the infinitive.

Could the pronoun le go somewhere else in the sentence?

Yes! While it is attached to the infinitive here (explicarle), you could also place it before the conjugated verb and say ¿Le debería explicar...? Both options are completely correct and natural.