Do piano composers often start out with C major?

Question

I'm wondering if composers write their pieces starting with C major since it's just the white keys, and then later transpose the finished song to the key of their choice? Or will starting with the intended key from the start produce better results?Edit: or "A minor" for minor songs

Answer 1

Most pianist learn how to play in the Key of C first before branching out to other keys. It is easier to learn the key of C first before the others, but a well balanced composer should learn to write and play in all keys.

Answer 2

A trained composer will be equally comfortable in all keys; the choice of key for a piece will usually have to do with the sound of the key (sharp keys seem brighter, flat keys seem darker to most people), or the ranges and restrictions of certain instruments. The key of G major, for instance, takes advantage of the lowest two open strings of the violin as tonic and dominant, the most important notes of the key.

C major isn't even necessarily the simplest key to play in—it's easier to play piano in keys that use a couple of the black keys than it is in C major or A minor.