When/should I add breath marks to my woodwind/brass score?

Question

I have two questions concerning how a composer writes breath marks in their score for brass/woodwinds:

First: Is it required that the composer notate breath marks where players can/should breathe, or would the composer leave that out and let players decide, in their own parts, when and where to breathe?

Second: When several players of a particular instrument section (such as four French horn players) are playing a long passage, do some players pause to breathe whilst others keep playing, thus producing a continuous tone, or do all players stop and resume simultaneously? If it’s the former, is there a way to notate that in a score (e.g., “Pl.1+2 breathe here” or something)?

Answer 1

No, breathing marks are not required. However, if it's important that breathing occurs at a specific place, then notate it. Especially if the location isn't intuitive.

If you don't write breathing marks, players will generally aim for the end of a phrase. At least, decent players will. If you're writing for a younger or inexperienced player, more notation can help. Your aim should be to communicate exactly the required level of detail. If it's obvious where I should breathe, don't notate it. The trick is figuring out what is obvious.

The easiest way to notate a continuous tone is to write "stagger breathing" or similar above the passage. This asks the players to coordinate their breathing such that the tone doesn't stop. You can also explicitly notate breathing to achieve the same effect.