I have to disagree with jainen.
Had the client come in for his appointment, said, "What do you need to start in terms of information from me and money down for you," my answer would have been very different.
But the ones who can't be bothered to come to their own tax appointment just don't take it seriously. There isn't enough money to make most of these people worth dealing with (for me). If you want him, jainen, go for it and more power to you.
I have plenty of work without taking on someone whose every action screams "Warning! Danger Will Robinson!" And I have learned the hard way to send those clients elsewhere.
Perhaps if I had a larger practice with several assistants to hound the guy with phone calls and not bring the stack to me until all documents were in hand, my answer would be different.