Yesterday and Back Then: Preterite vs. Imperfect
Use the preterite for completed events: Ayer llegué tarde, Hablé con Laura, Compré café, Fue caro. These are stamps in time with clear starts and finishes. When you can circle the moment on a calendar, the preterite usually carries the narrative punch.
Yesterday and Back Then: Preterite vs. Imperfect
Use the imperfect for context and repetition: Siempre tomaba café, Cuando era niño, Mientras estudiaba, Hacía frío. It paints the scene, describes ongoing states, and sets routines. If the action feels open-ended or descriptive, the imperfect keeps the background softly alive.