How many years until durian fruits and is it worth the investment in India?

Durian is a long term, high risk, potentially high reward crop in India, and you must go in with eyes open. Grafted trees take several years to begin fruiting and longer to reach good yield, while seedlings take much longer, so you carry orchard costs for years before any return. If you succeed, durian sells at a very high price as a rare exotic fruit because almost none is grown domestically and most is imported, so even a small quantity of good fruit can earn well from premium urban buyers, exotic fruit traders and online sellers. But the risks are real: unproven agronomy in Indian conditions, scarce planting material, the heavy perishable fruit, weather and disease threats, and uncertain yields, so treat any income figure as a speculative wide range, not a promise. Plant only a few trees first to learn, line up premium buyers, and expand only after you have actually fruited and sold successfully. Verify everything locally before committing serious money.