Investment fees (fund management charges, platform fees, transaction costs) compound massively over decades. 1.5% annual fee vs 0.2% on £100k portfolio over 30 years is roughly £400k difference. Annual audit identifies expensive holdings most adults ignore.
What to check
All fund expense ratios (target under 0.3% for index funds). Platform fees (Hargreaves Lansdown charges more than Vanguard direct). Trading frequency costs. Adviser fees if applicable.
What to do about it
Move expensive funds to low-cost alternatives (often same exposure at 10x less fee). Use cheaper platforms for new contributions. Cumulative annual saving compounds significantly.