Following the 12% drop in the U.S. stock market in April, a reader wrote me lamenting that he had to postpone his planned retirement this year, blaming “the Trump stock market crash.” In our couple of email exchanges, I asked some general questions about his plans and asset allocation. Instead of addressing those questions, he ranted about how he’d lost so much money because of Trump, somehow managing to include me in the supposed cabal responsible for his economic misfortune.

My final message to him, which should have been my first, was simple: if a 12% decline in the stock market forces you to postpone your imminent retirement plans, you aren’t ready to retire. That guy either doesn’t have enough money to retire, he has the wrong investment plan, or he is emotionally incapable of reconciling his assets, goals and fears.

I haven’t heard from him since the U.S. market has rebounded into positive territory for the year.

There are multiple ways to plan for retirement, but here is one general philosophy: if you aren’t going to touch your money for five years or more, bias toward having that money in stocks. Conversely, don’t put any money into stocks that you know you will have to spend in the next 3-to-5 years. If you know you are likely (or certain) to need money in the next few years, put that money in low-risk, principal-protected, short-term investments, ideally earning at least the rate of inflation. A money market fund can sometimes be a suitable vehicle for this, but be careful, as the yields on them can vary widely. While the top money market fund yields are currently greater than 4%, the average yield on U.S. money market accounts is a paltry 0.62 percent.

This five-year window is more than just a rule of thumb. The average length of time it has taken the stock market to fully recover following a bear market is 2.5 years. Sometimes it takes longer. It took about four years for the market to fully recover following the bottom of the 2007-2009 financial crisis, which saw a 50% market drop. Waiting for the recovery may not have been pleasant, but if you had enough liquid funds to meet five years’ worth of cash needs, you didn’t have to sell stocks at depressed prices simply to pay your bills.

Of course, there are other strategies for managing the balance between the need for cash and for growth; this is just one general framework. But if your retirement plans can change 180 degrees based on 4 weeks of stock market performance, it doesn’t matter what strategy you’re using – you aren’t prepared to retire.

David Moon is president of Moon Capital Management. A version of this piece originally appeared in the USA TODAY NETWORK.