Don't ask "Is it good?", ask "Is it effective?".
To know whether something is effective, you first have to answer another question: What is it for?
- What is the diet supposed to do?
- What do I want to accomplish by exercising?
- How do I want to use this skill?
Then another question: did it work? What do I need to know to determine whether it worked? Am I tracking that?
What's effective in your life?