As a friend in a tech industry, I tell all my friends to budget 50% of their revenue for tech investment and R&D. Oh and conveniently, I also have a company that can help them with these investments.

Seriously, don't swallow cock-and-bull statements like "legal should be 10% of your revenue". I remember years ago the landlord of my co-working space glibly told me that "as long as office rent is not more than 10% of your revenue you're good" in response to me pushing back to rent hike increases. Ridiculous conmen.