When I write down music, I always get confused about sharps, flats and natural symbols. Like if you have a note outside of the key signature and you put a flat,sharp or natural symbol on it, by the next measure are you supposed to assume that if that same note has no symbol then it's back to normal ? Or if the note is altered in one clef, but not the other, do I put a sharp/flat/natural symbol on just the one clef and leave the other one unaltered?
in situations like that i think courtesy accidentals are very important