[sheraz]

In the famous words of Ben Affleck's character in Good Will Hunting, "RETAIIIINER!"

(for levity) - http://www.youtube.com/watch?v=5hWIr9_noRo

Just as with other professional services (Law, Advertising, Accounting), I use a retainer model.

This works for me and filters out the clients who I feel value my work.

For example:

  * $10000 put into an account that draws down against hours worked / daily / weekly output.
  * Invoiced weekly through freshbooks 
  * As retainer moves below threshold in retainer it gets replenished.

This keeps all of us honest, and it keeps me in a cashflow positive situation (usually).

Also, read up on patio11's posts here on HN. He's a smart guy and offers a lot of insights into what it is like to consult for a living.