10,000-Hour Rule
It is recommended that in order to be a good and well-verse in your craft you will need to spend not less than 10,000 hours of dedication in your skills. You need to have practiced, to have apprenticed before acquiring expertise in your field.
Supposed you practiced 4 hours for any skills, it would take you 2,500 days, or approximately around 7 years of daily practice before gaining world class expertise.
Years to master the following:
Estimating for for 4 to 8 hours, it would takes 4 to 5 years.
Throwing dart for 30 minute, it would takes 55 years
Photograph for 2 hours, it would takes 14 years
Dog Handling for 1 hour, it would takes 27 years
Tattooing for 3 hours, it would takes 9 years