Inquiry: for parts of a piece/piece without a clear tonal centre how do we put accidentals?

Beyond simple general use of sharps flats and double sharps and flats, how do we decide which direction to go ( like go more sharps or flats on the circle or fifths) or is there a more underlying principal to this.

I currently have the below score, would like to know how should I notate the score for parts:

- that are not in a clearly stated key

- are mor more less in a key but they only last one/two bar(s), should I put key signature or just all the necessary accidentals?

- to make it consistent with the above options, for parts that are more or less in a certain key for over 4 bars, do I take away the key signature, maintaining the exact notes via accidentals?

https://musescore.com/user/62605720/scores/25131706?from=notification#comment-9314725

I'm asking cos a simple google and Ai search doesn't quite address my concerns above, and have not converted it into a vid to be posted elsewhere.

( ofc the scherzo thing is another thing but not my main concern here, maybe ill ask abt that later on in another post)

Thanks very much!

Where you have a key change that only lasts one or two bars, I think the usual practice is not to change key signature.

When the harmony is free roaming, it's quite common these days to have the whole piece in a neutral key (i.e. no key signature).

That would also apply to atonal works, or those with no clear tonal centre.

When there's a recognisable chord for a particular key, then you should use the enharmonic spelling for that key. (But you seem to have done this already in your work.)

Hello

This is an interesting question.
I think that whenever a piece is tonal, or has those roots, you have to specify tonalities in the armature.
Whether they are all put in every time you modulate may be a matter of style. In baroque they didn't use to change the key signature with modulations. In romanticism it seems to be the norm.
I think that leaving the score without any key signature is for atonal works, where all accidentals must be indicated.

In your work, which by the way is very good, there are moments that can be expressed in another way. For example here. That mix of measures with sharps and flats is a bit strange and I also think that for a pianist it can be confusing.
I would have continued with flats in bar 35, writing this bar, and bar 37 as Cb (which, yes, exists too). And in measure 39 place a key signature for Ab. What sounds there is an Ab6, or a G#6 (although in this case the F natural should be written as an E#).

Anyway, you can see everything...
I've always been amazed at what Schubert wrote in this piece. He already uses a strange time signature.
The whole piece is in Gb except for a bar and a half towards the end where he breaks the whole key signature and puts there chords like D, D7/C, Gm/Bb... and resets the original key signature...