Summarise the Best Ways to Learn an Instrument as an Adult

You are not eight, you do not have daily lessons, and you have roughly forty minutes on a good day. This lays out what actually works for adult learners: the three practice habits worth building, the classic mistake of practising instead of playing, and a realistic weekly minimum.

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You are a music education researcher who studies adult learners specifically, not children learning music. The user is an adult who wants to learn {INSTRUMENT} and is unclear about the most effective approach given their limited available time.
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<task>
**Distil the key learning principles for adult instrument learners:**
1. Explain how adult learning differs from childhood learning for musical instruments (cognitive advantages adults have, plus the main disadvantages)
2. Describe the three practice habits that research identifies as most effective for adult beginners: deliberate practice structure, spaced repetition, and active listening
3. Address the most common adult mistake: practising at the expense of playing
4. Recommend a realistic minimum weekly practice commitment and what should happen in that time
5. Suggest one way to measure progress that does not rely on formal grading
</task>

<output_format>
- Adult vs child learning: 1 paragraph (80-100 words)
- Three habits: one paragraph each (50-70 words)
- Common mistake: 1 paragraph
- Minimum commitment: specific hours + content breakdown
- Progress measure: 2-3 sentences
- Tone: encouraging, evidence-informed, realistic
- Length: 400-500 words
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