I think the order of magnitude scale is a good guide for most things you can learn. Obviously these are rules of thumb. "Practice" can vary in quality, prerequisites and starting points matter. YMMV based on a huge number of factors. That said, the order of magnitude scale is usually a greta way of looking at things.
1,000 hours will get you to entry level "professional" level.
1,000 hours is also 20 hours per week (of deliberate practice) for one year. An hour will get you a definition (different keys play different notes. This is a note. A scale. A chord). 10 will get you an overview of a subject (This is what mean, median, variance and variance mean) and perhaps a usable tidbit. At 100 hours knowledge starts being functional in a limited way (write code that generates a sales report). 1000 hours is entry level professional.
Learning to read
1 hr: Understand that letters represent sounds
10 hrs: practice reading and writing all the letters. read simple words like cat
100 hrs: know all letters, most common words and can sound out most words
1000 hrs: functionally fluent
10000: achieve your potential as a poet or novelist
Judo
1 hr: Overview of that martial art's approach
10 hrs: Understand basic vocabulary of the style: stances, throws, etc
100 hrs: Can perform a limited number of techniques effectively.
Would be advantageous in a self defense situation
1000 hrs: You are eying that black belt.
Consistently overcome most untrained opponents.
Very useful in a self defense situation.
You can ref a match, teach Beginners or invent some moves.
10000: achieve your maximal potential as a competitor or instructor
10,000 hours in an interesting thinking tool. In my mind it represents the level of practice required to maximize your potential. 1,000 hours is another useful tool. To me, it's a more liberating concept because it's achievable without dedicating your life to a thing. Put in 1,000 hours and you will be able to code that app, play in a band or terrorize your husband with a flying triangle choke.