If your home loan rate is around 8.5% and you have surplus cash, the question becomes whether investing that money could reasonably earn more than 8.5% after tax over the same period. Equity mutual funds have historically offered higher long-term returns, but with volatility and risk that a guaranteed loan interest saving doesn't carry — prepayment is a certain, risk-free return equal to your loan rate.
Prepaying early in the loan tenure has a much bigger impact than prepaying later, since more of your EMI in the early years goes toward interest, and reducing the principal early saves interest that would otherwise have compounded over many remaining years. The same prepayment amount made in year 15 of a 20-year loan does far less than the same amount made in year 2.
A reasonable middle ground many people use: maintain full emergency fund and insurance coverage first, continue regular investing for other goals, and direct only genuine surplus — a bonus, a windfall — toward prepayment, particularly in the earlier years of the loan when it does the most good.