I've found that an alternative to negotiating my rate is just giving them a day rate that basically works out to being a little less but locks me in for at least 8hrs. Basically, I'm discounting them the time I'd have to spend looking for & negotiating new business.
Generally I try and avoid quoting an hourly rate anyway. You're not paying me for hours - you're paying me for results.
The one discount that I do provide is for early payment - to give clients an incentive to pay earlier rather than the last-possible-moment. And that's planned - not off the cuff.
I agree with this 100%.
I'm not going to have a client watching every time I turn on my computer to work. Inspiration, ideas, results, all come at different times and sometimes shorter than others.
Anyone can learn to use a program, but you pay for the knowledge and creativity of the designer.