Ten thousand hours is not a threshold
Practice matters enormously and explains far less of the variance than the number suggested.
Do this
Focus on the quality of practice - specific weaknesses, immediate feedback, working at the edge of ability - rather than on accumulating hours. Expect the amount required to vary hugely by domain and by person.
Why it works
The figure came from an average among elite violinists in one study and was popularised as a rule it never was. A meta-analysis found deliberate practice accounted for around 26 per cent of variance in games, 21 per cent in music, 18 per cent in sport and under 1 per cent in professions. Ericsson disputed the methodology; the debate is genuinely unresolved.
Where it fails
The overcorrection is worse than the myth. Nobody reaches expert level without enormous focused practice - the finding is that practice is necessary and not sufficient, not that it is unimportant.
How you’ll know
Compare two hours of playing what you already know with twenty minutes on the passage you keep fumbling. Only one of them is the thing being measured.