How to Think About Investing Costs (Simple Framework)

Good investors do not only ask: “What return can I get?” They also ask: “What return will I keep after costs?”

The 4 cost layers

Product cost: ETF TER
Broker cost: commission / custody / inactivity fees
Execution cost: spread and slippage
Currency cost: FX conversion and FX spread

Simple formula mindset

Net expected return ≈ market return − total annual costs

Even 0.5%–1.0% annual cost gap can create very large differences over long horizon.

When costs become dangerous

Frequent trading
Small monthly amounts with fixed commissions
Repeated FX conversions
Stacked products with multiple fee layers

Cost-first checklist before investing

I know TER of each ETF
I know yearly broker/platform fees
I know per-order commission and spread impact
I know FX conversion model for my account
I estimated yearly total cost in euro and %

Practical rule

Keep portfolio structure simple, trade less, and avoid unnecessary cost layers. Cost control is one of the easiest ways to improve long-term outcomes.

Educational content only. Not financial advice.