These are the only times it's smart to make changes to your investment portfolio

Recent market volatility has many investors wondering if now is a good time to alter their investments.

The short answer experts generally advise? It's rarely actually a good time to make changes to your investment portfolio.

"Most investors who jump in and tweak their portfolios typically do it in response to market conditions and history has shown us this just doesn't work out in their favor," says Tony Molina, a CPA and senior product specialist at Wealthfront. "What often feels right when it comes to investing, is usually wrong."

Though you may feel tempted to modify your investments when the market dips, you're often better off leaving them alone for the long haul. The reality is, downturns happen but your money is safer if you ride out the storm. Just as quickly as the market can go down, it can also go up — and keeping your cash invested throughout these fluctuations is what helps your money grow over time. This is especially true when investing in index funds and ETFs.

But, we wondered, is there ever a good time to adjust your investments? Turns out, there are a couple conditions when it's OK.

While it's typically best to leave your investments alone, you may want to change course if there has been a change in your investing goals' time horizons, and consequently, your risk tolerance, advises Ivory Johnson, a CFP and founder of Delancey Wealth Management.

On one hand, you may find that you have extended the number of years until retirement and can take on more risk. Or, on the other hand, perhaps you're retiring sooner than you thought and shortening that timeframe means that you need to put your money in lower-risk investments.

Using a robo-advisor is an effective workaround to avoid having to worry whether your investments match your risk tolerance. Robo-advisors have users fill out a brief questionnaire that helps them know how to best allocate your cash depending on your investment goals and the top robo-advisors will regularly rebalance your portfolio for you as needed.

Betterment, for example, will recommend a stock-and-bond allocation based on your goals and adjust automatically whenever you make a deposit, withdraw funds or change your target allocation. Betterment's algorithms will also check your portfolio drift (how far you are from your target allocation) once per day and rebalance if necessary.

The automated investing platform through SoFi Invest®* automatically rebalances investors' portfolios as well, but on a quarterly basis. SoFi is a good option for investors also looking for lending products as SoFi members receive a 0.125% interest rate discount on SoFi's student loan refinancing and personal loans.

Johnson adds that he would generally change an investment allocation when a big event has taken place, such as a severe illness or a large economic windfall (like an inheritance). In both of these cases, an investor's need for capital appreciation reduces, he says.

Molina agrees that a good time for investors to make changes to their portfolios would be in response to major life events. Specifically, he means events that put the investor in a position where they would need to access their investments in the near future (three or so years). Examples include marriage, a family emergency or as an investor nears retirement.

"This would be a good reason to reduce their investment risk or pull out their funds altogether," Molina says.

Much of an investor's decision to change their portfolio in this scenario depends on how soon they may need to withdraw their funds. "In general, if you need the funds within the next three years or less, you may want to consider changing your investment strategy," Molina adds.

When it comes to investing in individual stocks, keep in mind that you should be using money that you are comfortable having tied up for at least the next five years. While individual stock investors are advised to hold for the long term (especially during times of volatility) in order to best maximize their returns, they may choose to sell a losing stock if it is more risk than they can handle and it generates significant financial loss. Investing in index funds and ETFs are an easy way to take on less risk and diversify your investments.

If you're thinking of adjusting your investments, most of the time it's probably not the best move for your long-term growth in the market.

The exceptions to this rule are if your time horizon and risk tolerance suddenly change. Another exception is if there has been a major life event where you no longer need your money to be invested, or where you could be better off financially with the cash accessible in your wallet.

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*INVESTMENTS ARE NOT FDIC INSURED • ARE NOT BANK GUARANTEED • MAY LOSE VALUE