What really interrupts compound interest is never just market volatility.

Many people know that compound interest is important.

Warren Buffett, Charlie Munger, index funds, long-termism—almost all investment books end by telling you the same thing:

Buy quality assets and hold them for the long term.

The principle seems simple, but actually doing it is far more difficult than imagined.

Charlie Munger once said that the first rule of compounding is: Unless absolutely necessary, do not interrupt it.

The importance of this statement precisely illustrates how easily compounding can be interrupted.

Why?

Because there are too many "absolutely necessary" things in life.

Unemployment, illness, family expenses, parents' retirement, children's education, career changes—these real-life pressures may suddenly require you to withdraw funds from your investment account.

More importantly, we, as investors, are also constantly changing.

Most people assume that their current self is their true, stable self. In psychology, there is a concept called the "end-of-history illusion." It means that people can clearly see how much they have changed in the past but tend to believe that their future self will not change much.

For example, looking back at yourself ten years ago, you might think you were naive; but standing here today, you might also think that your future self ten years from now will likely be the same as you are now.

However, related research shows that people of all ages, from 18 to 68, underestimate how much they will change in the future.

When applied to investing, this has a significant impact.

You might have planned to work hard, save aggressively, and invest for the long term. But a few years later, you may have children, your health may decline, work pressure may increase, and your family may need more of your time. Your consumption patterns, savings capacity, career plans, and risk tolerance will all change accordingly.

Once your life goals change, how can your financial plan remain completely unchanged?

This is the most easily overlooked aspect of long-term investing:

A long-term plan is not just written for your current self; it must also be something that your future, changed self can continue to execute.

When making investment plans, many people tend to go to extremes.

Either they are extremely aggressive, thinking that because they are young, they should go all in and ideally bet everything on the strongest assets.

Or they are extremely conservative, believing the market is too dangerous, so they keep large amounts of cash idle and dare not buy anything.

The biggest problem with extreme plans is that they may feel great at a certain stage but are difficult to sustain throughout a complete life cycle.

Of course, it feels great when you're fully invested and the market is rising.

But if you truly encounter a prolonged downturn, unemployment, illness, family expenses, or a market that doesn't rise for years, can you still stick to your plan?

Holding large amounts of cash certainly provides peace of mind.

But if you truly encounter a long-term bull market and watch quality assets continuously hit new highs, will you feel anxious about missing out and eventually rush in at high prices?

Therefore, what truly interrupts compounding is often not a single market fluctuation, but a system that is inherently unsustainable in the long run.

A long-term investment system truly suitable for ordinary people should keep one in a position of having choices.

Keep cash on hand. This way, when the market falls, you are not passively taking a hit but have the ability to continue buying.

Maintain a reasonable portfolio allocation. This way, you won't feel too bad about missing out during rallies, nor will you collapse due to being fully invested during downturns.

Hold assets of sufficient quality. This way, when you are temporarily caught in a drawdown, you have the confidence to let time work for compounding.

Keep the plan flexible. This way, when your life stage changes, you won't be held hostage by your past self.

Long-termism is not about stubbornly holding on.

Stubbornly holding onto garbage assets is not long-termism; it's an unwillingness to admit mistakes.

Long-termism is also not about never changing.

When a company's fundamentals change, when your cash flow changes, when family responsibilities change, when life goals change, your investment plan should naturally be adjusted.

What truly matters is:

Principles should be stable, execution should be flexible.

Stable is the direction:

Buy quality assets, control leverage, keep cash reserves, and compound over the long term.

Flexible is the pace:

When to add to positions, when to reduce them, how much cash to keep, what percentage a single asset should constitute—all these should be constantly adjusted based on market conditions and your own life stage.

The power of compounding lies in its need for time.

But the reason people find it hard to truly benefit from compounding is that we are always interrupted mid-way by emotions, pressure, temptations, and life itself.

Therefore, an ordinary plan that can be sustained for 20 years is often more valuable than a perfect plan that cannot be sustained for 2 years.

Compounding is not achieved through momentary impulse.

Compounding relies on not being easily interrupted.

And the best way to avoid being interrupted is to always keep yourself in a position of having choices.