I hope this is the right part of the forum to ask this question. The question is 'how long would you expect a brass or woodwind player to sustain a note before needing to take a breath' or would a second player take over the sustain in a seamless continuation if it was a particularly long piece.
I suspect there isn't a 'written in stone' answer to this as i would think a brass instrument takes more 'puff' than a woodwind instrument to play. I just wondered if there is a general rule when writing music to address this situation.
I hope i've explained the query clearly enough, as it's something I've often wondered about.