Fees compound too

The certain drag.

The arithmetic

A 1 percent annual fee is taken every year, from a growing balance. Over 30 years it can consume a quarter or more of the final total compared with a 0.1 percent fee.

Fees are certain; returns are not, which is why cost is the lever to pull.
Compare total cost including platform, fund and transaction charges.

Comparing honestly

Run the same projection twice, changing only the fee. Seeing the two final numbers side by side makes an abstract percentage concrete.