Front end rebuild - what's it worth?

I would "guess" book time would be in the 10 hour range. So what I want to know is, why wouldn't you charge book time? If it takes you less, that's the benefit of being an experienced mechanic. That's what people are paying you for, right? Why is it everyone and their brother expects the mechanic to bend over to give everybody a good deal? It's a big job, it should be a big price.