Imperfect past or Preterite past tense?


If the verb advances the narrative (even slightly),
If the action is limited in time (even if it takes 20 years!),
If the verb indicates a change in emotional or mental state,
If there is any indication to the beginning or end of the action,
If the verb merely describes what something was like,
If the verb is an ongoing action that is interrupted by another action,
If the verb interrupts another action,
If the verb is ongoing, expressed by "was ---ing" in English,
If the action is regularly repeated in the past,
Actions that someone used to do regularly,
If the action is a state of mind (with no change),
If the action expresses time,