If you think about opportunity cost, it might not be as much as you think. Sometimes there’s a fee for getting to the next stage quicker than doing it yourself. You’ll have to decide if the fee is worth it.

If you're a lone consultant, you likely spend more than 10% of your hours on "selling" your services, recruiting clients, etc. Especially since not every pitch works out. If you can get all of your sales&marketing and much of your scope negotiation done by someone else, that's worth 10% of the project cost because that's 10% of the project effort.

I've seen anywhere between 5-20% working as a freelancer/consultant in London. This is partly why I think clients are keen to respond to cold emails about work - it can save them a lot of money compared to using recruitment agents.

I make 110€ an Hour, so the agent gets around 1500€ from me each month.

However, a lot of the assignments are available ONLY through agents. So the alternative to 90% with an agent is not 100%, it’s 0%