It’s a common piece of advice that investors should only invest in riskier assets as far as they are comfortable, but in a video on the Fisher Investments’ YouTube channel, founder Ken Fisher debunks that myth. “The scary part” of markets “comes and goes,” Fisher contends, and an investor’s comfort level is a fluid thing, changing from one point in time to the next. Therefore, if an investor follows the advice to sell only at their comfort level, they could wind up buying high when things look particularly good, and selling low when things get uncomfortable.

But investors “don’t need to think that way,” Fisher says. He likens that comfort level to a grandfather clock; when you first install one into your house, you can’t sleep because it’s going off all the time. But after a while, you no longer hear it. Market volatility is “much the same way,” Fisher stresses. It’s usually advised that investors have a portfolio with a high fixed-income allocation so that any volatility in the equities market won’t pain you too much. But most investors have a much longer time horizon that their assets need to last than they realize, and the last thing you want is to run out of money in your later years. That means having a greater equity allocation until much later in life, because in the long term equities “routinely do better than alternatives, or only a little worse,” Fisher says.

By focusing on the long term, just like with the grandfather clock, eventually the short-term volatility will be tuned out. After a number of cycles, you will get more comfortable with volatility and therefore avoid the buy-high, sell-low trap that will do more damage than the volatility in the long run, Fisher advises.