A newcomer should receive the same courtesy on their fifth question as on their first.

Patience usually has a limit that nobody states, and the newcomer discovers it by crossing it. The first question gets a warm answer, the third a shorter one, the fifth a tone. From then on they stop asking and start guessing, which produces exactly the mistakes the questions were preventing. Nothing was gained by the sigh.

Decide in advance that questions are part of the job rather than an interruption to it. If the same one keeps coming, write the answer down somewhere they can reach it, which fixes the cause instead of the person. And if you feel your patience going, say you will come back to it.