I have had some problems with this. Since I work by myself and work on-location, the cars generally take the entire day to do, so a cancellation is a major problem without a couple days notice. I often times cannot fill the day after the person cancels, so I loose the entire day's work. When they give me a week or so notice, there is no problem. I can find someone else. But I've had a number of 'oops I need to use the car TOMORROW' so you can't come and work on it, calls. It is too late to find someone else by that time!! I once had a lady TEXT MESSAGE (not even bother to call!) me while I on my way to the job to cancel!!!! I had trouble restraining myself from not calling her and yelling..... but I did end up getting to do her car like 2 weeks later.