Editor's note: The stock market has marched almost straight up for more than a decade...

But just because this is the longest bull market ever doesn't mean it will end next week. It could go on for weeks, months – or even years. However, as regular readers know, the warning signs are starting to mount... So it also could end sooner than you might think.

The point is, you could drive yourself crazy – and wreck your savings or retirement – by trying to time the market. Instead, as senior portfolio manager Austin Root discusses in today's Masters Series – adapted from the April issue of Stansberry Portfolio Solutions – you should always do a couple of things to make sure you're prepared for whatever happens...

How to Make Sure Your Portfolio Is Ready... No Matter What Happens Next

By Austin Root, senior portfolio manager, Stansberry Research

Do you know how to read markets as well as master investors Steve Cohen, George Soros, or Steve Sjuggerud?

If the answer is yes, this essay does not apply to you. Consider yourself exceptionally fortunate. But for the rest of us mere mortals, I invite you to keep reading...

Over the course of my 20-year investment career, I've had the pleasure and rare honor to work with all three of these otherworldly market mavens. And in that time, I've discovered some near-universal investing truths...

They're a set of fundamental rules that help to level the playing field. Adhering to these guidelines will materially improve your investment returns. These truths include...

1. A stock can always go lower, so honor your stops and other sell disciplines.

2. Establish clear investment goals and then stick to your plan for how to achieve them.

3. The only truly guaranteed way to grow your wealth over the long term is to spend less money than you make each year.

4. Invest in what you know and understand, because you'll make better decisions when the unexpected happens.

Today, I want to focus on a fifth investing truth... Do not try to time the market.

Don't do it... at least not in an all-or-nothing manner.

This means don't sell all your assets and go to cash in an attempt to avoid the next downturn before it happens. Most of us shouldn't even sell half our assets.

You may be asking, "Why not? What if I'm certain it's the right time to get up from the table and walk away?" But here are three reasons why you should never try to time the market...

First, there's a good chance you're wrong.

You see, predicting bear markets is a really hard thing to do...

Bear markets seem so obvious after the fact. But before they occur, it's tough to know when the music will stop and stocks will start trending down. That's because you'll see a lot of early warning signals – like slowing global growth, an inverted yield curve, widening credit spreads, and high valuations for stocks, among others – often before the crash actually occurs.

If you sold your assets at the first sign of these signals, you would have pulled out of stocks many times over the past 10 years... only to see the market rip higher.

Second, even if you defy the odds and correctly time when to sell, your work isn't nearly done. You'll also need to know when to buy back in.

Sitting in cash means missing out on one of the greatest wealth-compounding investment vehicles on the planet. Since 1900, U.S. equities have returned 6.5% per year – after inflation – according to the Credit Suisse Investment Returns Yearbook, an authoritative source for long-term returns. That's compared with an average loss of more than 3% per year in the purchasing power of cash. (That performance would be even worse if we see a spike in inflation.)

What's more, knowing when to buy can often be harder than knowing when to sell because markets tend to recover before economic data points actually improve. In fact, the data may still be getting worse when a market turns back up – just less worse.

Thus, I see market-timers miss out on big recoveries far too often because the data that got them out of the market still looks bad... while stocks rip higher.

With a market-timing strategy, you need to get both the sell and the buy right. It's hard enough to do even one of those things. To beat the compounding power of owning stocks over the long term, you have to keep being right on both sides over and over and over.

The third reason not to be a "sell it all" market timer is that there's simply a better way to invest.

It's what Doc Eifrig calls the "tilt"... As he has written, "You don't have to bet all your money on stocks, predict a top, and then pull it all out. Rather, you should just tilt your portfolio a little more or less aggressively, depending on how comfortable you feel with the market."

This strategy of moderation makes a lot of sense to me. And it works because it keeps you invested in bull markets that can start earlier and last longer than the false signals would suggest.

Of course, as always in investing, nothing is set in stone...

A market-timing strategy in which you sell all (or most) of your assets is appropriate if you simply need the money immediately... or if you are at a point in your life where your desire to preserve existing wealth vastly exceeds your desire for future capital appreciation.

True market mavens like Mr. Cohen, Mr. Soros, or Dr. Sjuggerud have more luck than the rest of us with timing the markets. But even they would tell you to only do so by leaning heavily into your portfolio tilt. No one is perfect, but these guys will give you a considerably better chance to succeed with such a strategy.

I'll share one additional reason not to sell it all right now. And I want to note ahead of time that this view is not shared by everyone at Stansberry Research...

I believe this bull market still has years left in it.

Contrary to the headlines on CNBC, bull markets do not die of old age alone. Something must trigger a prolonged and sustained drop. Usually, that happens when the economy is weak and in decline. But that's not the case today. The global economy is still growing (albeit at a modest pace).

More important, it appears that it has simply become politically untenable to have a weak economy. President Donald Trump won't allow it. You can see that in his pro-growth policy priorities, including the 2017 tax bill he championed that reduced the corporate tax rate from 35% to 21%.

And with the Federal Reserve halting interest-rate increases indefinitely – even signaling the potential to reverse course and lower rates should growth stall – it's clear that Fed Chairman Jerome Powell is on board with extending the strong economy as well.

So I don't want you selling out of your stocks just yet. This bull still has some run left in it.

But I do still want you to be cautious. I still want you to invest in portfolio protection and some safer income-oriented investments. I still want you to own high-quality, capital-efficient companies with strong balance sheets and durable business models.

Because I could be wrong. And you'll need to own sturdy assets if the markets get really bad sooner than expected.

Good investing,

Austin Root

Editor's note: You should never sell everything and go completely to cash... But you should always be ready for what comes next. During our Bear Market Survival Event on Wednesday, Porter and legendary investor Jim Rogers explained why the next crisis will be the worst in our lifetimes... how to know when it's arriving... and what to do to grow your wealth while others struggle. For the next few days, you can watch a free replay right here.