If a couple, right after their marriage, begins investing Rs 5,000 every month at an assumed annualised rate of 12 per cent, they would be able to build a retirement corpus of Rs 1.75 crore after 30 years. But if they start investing after 20 years of their marriage, they would require to invest Rs 76,000 a month to build the same corpus at the same rate of return within the same time. Working couples, therefore, must consider investing as early as possible in equity mutual funds for their long-term financial goals as equity as an asset class beat both inflation and fixed income investment instruments by a wide margin over the long term.