It sounds like you prefer fixed scope of work for a fixed price? How do you adjust when your estimate of delivering a specific objective is off? And how do yo

It sounds like you prefer fixed scope of work for a fixed price? How do you adjust when your estimate of delivering a specific objective is off? And how do you factor that into your schedule if you have commitments with other clients? I can see this being a lot different for someone providing a week of SEO consulting vs. a week of software development, for example. Two hours of keyword research always takes exactly two hours. But if $FOO and $BAR are software features which involve third party integration or dealing with race condition bugs that are difficult to pin down, one week can easily turn into much more.