Actually, I retract this statement. People who ask for a 30% discount don’t deserve any discount, imo, and budging even a little will only reinforce their behavior.
As others have mentioned, people like this tend to be the pickiest and hardest to work for. When they’ve gotten their way at the beginning, they will only get worse to work for. In general, they do not see people in service work as equals, and will try and ‘tilt’ the relationship in their favor. Occasionally, you can “step up” to their level by sticking to your guns, and they will then treat you with some respect. But it’s a pretty rare occurrence, in my experience.
Bottom line, If you happen to lose this sale due to not caving on price, it’s a good thing.