New Delhi, July 10 -- Choosing the right mutual fund is often seen as the key to successful investing. Investors compare past returns, fund managers and expense ratios before deciding where to put their money. However, according to wealth managers, the biggest threat to long-term returns often has little to do with fund selection.

"A mediocre fund might cost you a couple of percentage points a year. Bad timing can cost you the better part of the compounding altogether," said Bhalchandra Joshi, Chief Business Officer and Chief Operating Officer at The Wealth Company Mutual Fund.

Here are three mistakes experts say investors should avoid.

Market declines often trigger panic among investors, prompting many to redeem their mutual fund inve...