Final answer:
The sentence should be written once before the exhibit opens and everyday for the length of the exhibit.
Step-by-step explanation:
The question asks how many times the sentence should be written after the exhibit closes. The sentence should be done floor to ceiling at least once before the exhibit opens, and should continue daily for the length of the exhibit.
Therefore, the sentence would be written once before the exhibit opens, and then everyday for the duration of the exhibit. In standard letter-writing etiquette, it is typical to hit the Enter key twice following the complimentary close, before typing your name or signature. This practice creates a space that visually separates the closing sentiment from the signature and provides a neat and professional appearance to the letter.