Learn Italian: Noleggiavo un film e non dormivo. - I used to rent a movie and I wouldn't sleep.

The imperfetto is used because this describes a repeated, habitual action in the past. The English translation shows this with "used to rent" and "wouldn't sleep". If you used the passato prossimo, it would mean this sequence of events only happened once on a specific night.

How are the endings for noleggiavo and dormivo formed?

Both are regular in the imperfetto. You take off the infinitive endings from noleggiare (to rent) and dormire (to sleep) and add the first-person singular (io) endings. Notice how the vowel matches the infinitive: -are verbs take -avo (noleggiavo), -ere verbs take -evo, and -ire verbs take -ivo (dormivo).

Why does the English translation say "wouldn't sleep" for non dormivo? Isn't "would" a conditional word?

In English, we often use "would" to describe a past habit (like "when I was young, I would stay up late"). Because it describes a past habit, Italian uses the imperfetto. You only use the Italian conditional tense if "would" means a hypothetical situation (like "I wouldn't sleep if I drank coffee now").

I noticed film is used here. How do you say "movies" in the plural?