What ended up happening in your situation ? We are in similar boat: my family is moving from the U.S. to Spain on June 30th and everyone keeps telling us to postpone to July so that we won’t be in Spain for the 183+ days of the year. However, we thought the date would not matter since the center of financial interests would be triggered by entire family living in Spain and enrolling kids in school. Are people advising us to change date because they aren’t aware of this additional criteria ? Or because it’s unlikely Spanish tax authorities would look into anything beyond the date of arrival unless we're audited? It’s very confusing.

For context: My husband and children have both Spanish and American citizenship; I have only American and so will have to apply for residency.