Tickets will be distributed on a first-come, first-served basis. (Hyphens needed<br/>here--yes or no?)<br/><br/>Tickets will be distributed, first come, first serve. (No hyphens, because the phrase is not modifying a noun, correct?)<br/><br/>It was an on-again, off-again relationship.<br/>(Hyphens required?)<br/><br/>The relationship was on again, off again. (No hyphens, correct?)<br/><br/>Thank you.