Ah, math. Learn it. Know it. Live it.
There comes a point in your design career when you stop expecting clients to tell you the truth. It is, perhaps, a very cynical moment, but it will come. When you start out all wide-eyed and bushy-tailed, you bend over backwards to suss out the insane double speak that clients use during the course of a project. As you get along in years and work with many more clients, you realize that understanding such nonsense is absolutely impossible.
So you learn to say “no.”
“No” is tough, especially if you’re freelancing. You need work to pay the bills. Turning down work means turning down money which potentially means turning off your electricity. But the hard truth is that there are certain gigs that would cost you much more than you’d make. “No” can sometimes save you money.