The 10k hours rule states that it takes 10k hours to become a master at a skill.
If you are talented, perhaps it will take less time than that. But that’s just a ballpark figure. Not all hours are equal though. The hours should be spent on “deliberate practice” for best results.
But that’s for Olympic-level/world champion-level expertise. What if I want to be just “decent” at a skill? How many hours do I need?
Surprisingly, you only need around 20 hours of deliberate practice for that. There is a whole book on this topic: The First 20 Hours – How to learn anything fast.
Learning a skill has diminishing returns. So while you can become decent in just 20 hours, it takes far longer to become a master. But hey, if you plan things right, you can quickly become a jack of many trades!