The stock-market whiplash this week shows why you shouldn't worry too much about your 401(k)

• The stock market this week had a scary day on Monday and a great day on Thursday.
• Temporary declines are a normal part of the stock market's cycle.
• Long-term investments in the market generally recover from slumps, a financial planner said.

The stock-market downturn on Monday was sparked partly by a rise in panicked speculation about whether a recession was coming — and with that came fears about what the sell-off might mean for retirement accounts such as 401(k)s, which are often heavily invested in stocks.