Is it worth doing an annual health check-up if you feel fine?

A targeted one, yes; the comprehensive packages sold by most labs, less so. Broad panels generate incidental findings that lead to more tests and anxiety without improving outcomes, which is why blanket annual screening is not recommended in most guidelines. What is worth doing, particularly in India: blood pressure, blood sugar or HbA1c, a lipid profile, haemoglobin, and thyroid where indicated — with frequency depending on age, family history and risk. Vitamin D and B12 are reasonable once given how common deficiency is. The value comes from acting on results, which most people do not.