DS2 has wanted to learn an instrument for a while. We told him to wait until he was 7, which he now is.
He has the choice of private piano lessons (which DS1 already does), or woodwind, brass or strings through school. Initially he wanted to learn piano the same as his brother, but now he has expressed an interest in the trumpet. I think he would suit the trumpet as he is quite a "character", unlike his older more studious brother who is quite happy to do half an hour's piano practice every morning before school.
The only thing that worries me though is the fact that he doesn't have his top adult teeth yet. Will this mean he can't play brass instruments yet?