For example, the sentence "Cuando era niño, fuimos a Idaho" would normally be understood to mean roughly "when I was a boy, we took a trip to Idaho." But Cuando era niño, íbamos a Idaho would normally be understood to mean roughly "when I was a boy we customarily went to Idaho."
However, there are at least two cases where the preterite tense should be used when speaking of repeated events:
- When the number of repetitions is stated: Cuando era niño, fuimos diez veces a Idaho. (When I was a boy, we went to Idaho 10 times.)
- When the emphasis is on a beginning and/or end to the repeated action: Cuando era estudiante, Pablo se durmió temprano todas las noches. (When he was a student, Pablo fell asleep early every night.) The imperfect tense could also be used here, and in most cases would be preferred. But by using the preterite tense, the speaker is placing a strong emphasis on the fact that Pablo quit going to bed early when he was no longer a student, or that he didn't start going to bed early until he became a student. The going to bed early in the sample sentence is thought of as more of an event rather than background information.
Similarly, the imperfect tense is typically used when speaking of emotional states in the past. However, the preterite can be used when the emotional state is thought of as an event rather than background.
- Al ver la injusticia, me enojé. (When I saw the injustice, I became angry.) In this example, getting angry is clearly an event, not mere background.
- Siempre fui triste y me sentí extranjera en todas partes. (I was always very sad-natured and I felt like a foreigner everywhere.) The speaker also could have used the imperfect tense and been grammatically correct here. In fact, in most cases the imperfect would be preferred in a sentence like this. However, by using the preterite, the speaker puts an emphasis on her feelings as an event: Perhaps they were short-lived, or perhaps because they were precipitated by a specific incident.

