Depends on the clock.

But seriously, I's say it's only a matter of pitching it where the instruments can play it (or not, I do a number in F sharp-ish) and the singer can sing it best.

When my late wife was alive and we were trying to arrange songs so that they would work on guitar and recorder and fit both voices there was more than one occasion when we went all the way round the octave and still were not happy!