That might be true if you just take blanket advice. The key is to find out why say StringBuilder is better than String.Concat. If you understand the implement

That might be true if you just take blanket advice. The key is to find out why say StringBuilder is better than String.Concat. If you understand the implementation details and tradeoffs involved, this makes the knowledge much more applicable in the future. The core concepts in technology do not move nearly as fast as individual projects, libraries, frameworks, languages, etc...