Picking the correct key

[maxym.srpl]

I’ve noticed that some music is written in C major, others in A♯/B♭ major, D major, E major, etc. What factors influence an artist’s or composer’s choice of key?

Even watching videos of known producers, they change a key from song to song.

let’s stick to electronic instrumental music, to avoid a singer vocal range issues.

with regards

[Jamface]

I often hear ideas in my head first. So the key gets decided at that point, mostly. At other times, I’m just improvising at the piano. Something will catch my ear… and there’s the key.

[zerocrossing]

The key initially becomes whatever pops out of my head, though sometimes I'll change it to accommodate my voice, though I've recently given up singing due to having a small range and having better synthetic alternatives.

Oh, I should also comment that a lot of the time the key is dictated by the fact that I'll sometimes write for guitar.