Most people look at their retirement statement, see a single "total fee" line, and move on. That single number is almost always the sum of three separate fees being charged by three separate parties. Knowing which is which changes what you can do about them.
The fund fee.
Paid to the people who actually manage the money: picking shares, running the portfolio, trading. This is usually the largest of the three. It varies enormously between active funds (often 1.0% to 1.75%) and passive index funds (often 0.1% to 0.4%). Switching from active to passive, where appropriate, is the single biggest fee lever most people have.
The platform fee.
Paid to the LISP or administrator that holds your money and handles the paperwork. Usually between 0.25% and 0.75%. This one tends to be the hardest to feel, because it's just "infrastructure", but the range across providers is wide enough to matter.
The advisor fee.
Paid to the person giving you advice. Usually 0.5% to 1.5%, often 1% in South Africa. This one is the most visible and the most controversial, because the value can vary most. A good advisor earns this easily. A bad one earns nothing.
Putting it together.
Your "all-in" fee is usually somewhere between 1.5% and 3%. The difference between those two ends, over a working life, is the difference between retiring on time and retiring years late. That's why it's worth knowing which piece is which, and whether each is earning its keep.