You may want to check out Cortot, who did a series on how to practice Chopin pieces, notably the notorious Etudes. One of the techniques he describes is varying

You may want to check out Cortot, who did a series on how to practice Chopin pieces, notably the notorious Etudes. One of the techniques he describes is varying either rhythm or accentuation. I tried especially the latter which works pretty well. But I am a bit unsure whether it is a genuine effect or a consequence that a practice a chunk more often if you do this.