That's a good rule of thumb, but a better rule is probably to just get an accountant on day one. For 1099 consulting businesses, doing your own taxes is probably a false economy.
I think a lot of people assume they can put off getting an accountant until they're sure the business is serious. Which is probably why so many of the stories I've heard (and, to add to that, my own story) are about the tax screwup consequences of those first couple gigs you do before you formalize the company.
Sure you should get an accountant. But you should still reserve that much money.
Getting an accountant is your first major purchase as a new business owner.
And getting a good one is not all that easy. I lucked out, the one I ended up with (after trying two others) was a CFO of a large company that decided he had enough of the pressure and joined his wife's fledgling accounting company.
So instead of just having an accountant I ended up with a mentor to boot, all for the price of one.
I think a lot of people assume they can put off getting an accountant until they're sure the business is serious. Which is probably why so many of the stories I've heard (and, to add to that, my own story) are about the tax screwup consequences of those first couple gigs you do before you formalize the company.