I'm kind of half way in between . I usually have a contract, always if it is a new customer. My contracts are much simpler, although I do try to list all components of a job. I would feel a bit taken back, if I were a customer of mine, with the adversarial tone of some of the parts of the above contract.
But if your relationship with the client becomes adversarial, it is needed.
And I also think there is a difference in a 1 or2 guy shop , where the client has the person who they originally talked to, who comes and does the look and wrote the bid, and then shows up to do the work. Much different than a biz with a different guy for each stage. Much more personal. And it's harder to stiff someone your more personal with. Not impossible, harder.