Actually, the 10 000 hour rule was a misinterpretation of data, and the real result was that if you have the genes and the ambition you may become a master in your area of expertise, if you practice between 3 000 and 30 000 hours, i.e. a completely meaningless and useless result.
On the other hand, there is a 20-hour rule that is immensely more useful. If you focus and practice intelligently for 20 hours on learning a new skill, you will become "quite proficient". I'd say, if you put in 100 hours (1% of 10 000 hours) you will leave most of mankind behind in that area, often achieving about half the level of a professional.
Since you have a lot of 100 hour chunks at your disposal, you can become an instant expert in hundreds of useful or entertaining skills. If nothing else, you can find out where your talents are and what satisfies you the most, rather than arbitrarily chosing chess, golf or tennis and end up wasting 10 000 hours on something you don't really enjoy and won't master anyway.
I live by the 1/50 rule: 1% effort for 50% of the gains:
I work out 3-4 hours a week, in practice 2% of the available time over a year, doing only heavy compound exercises with free weights. The only cardio I do is 5 minutes warm up on a tread mill. My body fat is 9% (yesterday) and I look like this at 42, despite sitting at an office desk for 20 years, eating a lot of red meat, french fries, ice cream and drinking a lot of alcohol (e.g., on Ibiza in July):
Cooling down after a sauna last Sunday
I drink a table spoon of Omega 3 oil every day, but eat whatever I like the rest of the time (I am never ill and my bloodwork is exceptionally good, e.g., Omega 6/3 balance of 2 and very low cholesterol)
I do mobility exercises about every second day: couch stretch, squat and sholders. You don't have to hurt yourself doing splits or tormenting your hamstrings to be healthy, or stretch every second day for that matter. Just do these three exercises about once a month and you'll keep that old-man-walk at bay for decades more.
I try new stuff every now and then, e.g., juggling, portuguese, hand stands (NB: just because you started something you don't have to keep at it. Dare to give up, walk away or simply be satisfied by knowing the basics. 20 hours is definitely enough to see if you like it)
- Forget about the 10 000 hour myth
- Try a lot of new things for 20 hours
- Don't be afraid to walk away from something you started