THERE ARE ONLY FOUR SKILLS: DESIGN, TECHNICAL, MANAGEMENT, AND PHYSICAL

Summary from the TLDR Dev newsletter

All human skills can be categorized into four fundamental types: Design, Technical, Management, and Physical. Conscientious individuals who are expert in one task within a category can achieve expert-level proficiency in any other task within that same category in approximately six months of focused effort. However, acquiring expertise in a different category requires a lot more time and effort, as they are distinct cognitive domains.