What is reasonable to sign for a non-compete form as a photographer, and what is not?

I had to sign one once to work for a company, the contract was so I would not use the company's business model to compete. They sold to schools and sports clubs and they didn't want me to copy their method of obtaining jobs. I was still able to do weddings and portraits or I wouldn't have signed. In fact I was allowed to use a duplicate camera to keep my work if I wanted to, even though the images were also contractually theirs.