Every trade costs twice

Buying and later selling the same thing usually means paying a fee twice: once going in, once coming out. More trades means more of these double costs.

A strategy that trades often needs bigger gains just to cover its own costs before it can start making real profit. Fewer trades means fewer costs eating into the result.

Ten trades a year at €5 a side (buy and sell) is €100 a year in fees alone, before any gain or loss on the trades themselves. A buy-and-hold approach skips most of that.

A small per-trade fee feels negligible. Added up across a year of frequent activity, it can quietly become one of the biggest costs in the whole plan.

Portfolio's Transactions list adds up every fee paid over the last year, so the real cost of trading activity is one number, not a guess.

Every trade costs going in and coming out. Fewer trades usually means fewer costs eating the result.