Be wary of contractors who say something needs fixed right away, especially if you didn't seek them out.
Shop around to get estimates and other opinions.
Request a list of references from the business or contractor.
Ask for a written, itemized contract of the work that will be done and the costs associated with each item.
Never pay the whole cost up front - wait until you are satisfied with the level of completion.
If you think you have been targeted by a home repair scammer or other fraud, contact the Attorney General's office in Phoenix at 602-542-5763, in Tucson at 520-628-6504 or outside of metro areas at 800-352-8431.