After exploring the lessons we can learn from the books of great investors, a practical question naturally appears: how do we apply those ideas when selecting real investments? One of the first things experienced investors examine is not the advertised return, but the real cost of a fund.

At first glance, costs may seem like a minor detail. The difference between 0.10% and 1% per year appears almost insignificant. However, in investing, small differences repeated over many years can lead to completely different outcomes.

In fact, costs are one of the few elements that investors can control.

Future returns are uncertain. Markets may rise or fall. The economy may expand or slow down. But the fees you pay for a fund are known from the beginning.

For this reason, disciplined investors pay close attention to them.

The first indicator most investors analyse is the TER, or Total Expense Ratio.

This represents the annual percentage that the fund deducts for management, marketing, operations and other internal expenses. TER is expressed as a percentage of the fund’s assets and is automatically deducted from the investment value.

For example, if a fund has a TER of 0.20%, it means that for every 10,000 euros invested you will pay around 20 euros per year.

That amount seems small.

Yet differences become meaningful when two funds are compared over long periods.

Imagine two simple scenarios.

One investor places 10,000 euros in a fund with an annual cost of 0.20%. Another investor selects a similar fund but with a cost of 1%.

If both funds generate the same gross return, after 20–25 years the difference in accumulated capital may reach thousands of euros.

This happens because fees reduce the power of compound interest.

Compound growth works best when costs remain minimal.

From my experience, many beginner investors focus heavily on past performance and completely ignore cost structures.

The problem is that historical returns guarantee nothing. Fees, however, will continue to be paid regardless of market conditions.

Another important aspect is the difference between visible and hidden costs.

TER reflects the main expenses of the fund, yet there are also indirect costs that can influence performance.

For example, some funds trade their holdings very frequently. Each transaction generates commissions and market costs.

These expenses are not always obvious in the initial fund presentation, but they can still reduce the final return.

Another element worth analysing is tracking difference for funds that follow an index.

An index fund should theoretically replicate the index performance as closely as possible. In practice there is almost always a small gap between the fund’s return and the index.

This difference appears because of costs, replication methods and operational factors.

If the gap becomes too large, it may indicate an inefficient cost structure.

Another potential cost is the entry or exit fee.

Some funds charge investors when they buy or sell units. These fees may vary from small fractions of a percent to more significant values.

In long-term investing such costs can reduce returns considerably if applied frequently.

For that reason many investors prefer funds without subscription or redemption fees.

Another important factor is the management style of the fund.

Actively managed funds usually involve higher costs because teams of analysts and portfolio managers attempt to outperform the market.

Passive funds that simply track an index typically have lower costs.

This does not automatically mean active funds are a poor choice. Sometimes they deliver strong performance. However, to justify their higher costs they must consistently outperform the market.

History shows that achieving this over long periods is difficult.

Because of this, many investors choose low-cost funds as the foundation of their portfolios.

Another element worth examining is the size of the fund.

Very small funds may have higher costs because operational expenses are shared among fewer investors. On the other hand, extremely large funds may become less flexible in certain strategies.

There is no perfect size, yet these details can offer clues about management efficiency.

Over time I started viewing costs as a form of financial friction.

Just as friction reduces the efficiency of a machine, excessive costs reduce the efficiency of an investment.

Sometimes the differences appear small on paper, but over periods of 10, 20 or 30 years the impact becomes visible.

Another thing I recommend is not analysing costs in isolation.

They should be considered together with the fund’s strategy, portfolio structure and your own financial objectives.

A very cheap fund is not automatically the best choice if it does not match your strategy. At the same time, an expensive fund deserves careful evaluation to determine whether it truly provides additional value.

Efficient investing is not only about selecting good assets, but also about reducing unnecessary costs.

This is one of the lessons that repeatedly appears in the experience of successful investors.

Over the long run, the difference between an efficient portfolio and a mediocre one is often influenced by seemingly small details.

Costs are part of those details.

And the question worth asking yourself is this: when you choose a fund, do you truly analyse all its costs, or do you only look at past performance?