My answer to that would be a definite yes. The formal and informal uses can be very important in their specific contexts in Spain, and particular in written Spanish; any classes or tests that I have done have emphasised it, and you can lose marks. Equally you can gain them by picking up on the less obvious ones - like talking to a police officer (or asking someone for help) where formal gets you real kudos especially in a live situation i.e. not only that you are treating them with respect, but that you can speak Spanish!
I travel to parts of Spain where the formal is rarely used, but I am often surprised how often it still comes up in shops and even some restaurants. Maybe it is because I am getting older and probably look it, but that actually makes the point. I think it's a good rule to learn, and to use the formal if in doubt. If the person answers you with the informal it is a good way to learn.
Yes, if they specify in the exam question that you need to use the informal or the formal you, they you'd be marked wrong if you use the one that doesn't apply.
Here is a lesson that will help you identify the different situations when you use one or the other: tú vs usted
Sign in to submit your answer
Don't have an account yet? Join today
Test your Spanish to the CEFR standard