Personally speaking, I don't like the headaches. I prefer to quilt to my own heart beats and give them away to people who probably want them.
It's REALLY hard to 'hear' exactly what someone else wants. If you're going to make a quilt for someone, it's probably best to have them buy the fabric and pick out the exact pattern, so there won't be any misunderstandings. AND agree on exactly what you're going to charge - per hour, per inch, per whatever -before any buying by either of you happens.