The writers who improve fastest are not the ones who write the most and I think understanding why matters more than most productivity advice acknowledges
Something I have watched play out in writing communities over several years and want to put somewhere useful.
Output volume and improvement rate are not the same thing and treating them as equivalent is probably the most common mistake serious writers make. The advice to write every day is genuinely useful but it is incomplete in a way that matters because it addresses quantity without addressing what determines whether the quantity produces growth.
The writers I have watched improve most visibly share something that has nothing to do with how much they write. They are unusually honest about what is not working in their own work and unusually specific about why. Not just this scene feels flat but this scene feels flat because the character wants something I have not established clearly enough for the obstacle to create real pressure.
That specificity is the thing. Vague dissatisfaction with your own writing produces vague revision. Specific understanding of what is wrong and why produces changes that actually fix the problem rather than moving it around.
The gap between writers who compound their improvement and writers who plateau at a competent level is almost always a diagnostic gap rather than a talent gap or an effort gap. The one who improves faster is not working harder. They are looking at their own work more honestly and more precisely and then doing something targeted with what they find.
The question worth sitting with is not how much are you writing but how clearly can you name what is wrong with what you just wrote and whether you have a reason for why it is wrong rather than just a feeling that it is.