Steve Zelle, an identity designer, chimes in about why he thinks billing by the hour is a bad idea.
You really can’t force creativity to happen. There are ways to encourage it and a process is there to help direct it, but in the end it has to just happen. So while a project may only take an hour at a desk, I can assure you more time was spent thinking about it.
The post has a number of interesting comments as well — so don’t miss them.