• Does not list a number in the phone book.
• Asks you to get required building permits.
• Only accepts cash.
• Solicits door-to-door.
• Says you will get a discount if you find other customers for that contractor.
• Uses left-over materials to complete your job.
• Tells you your job will be a demonstration.
• Offers exceptionally long guarantees.
• Asks you to pay for the entire job up front.
• Suggests you borrow money from a lender the contractor knows.
• Try to scare you into signing for repairs that they say are urgent.
• Demands a lien on your property.

Always read and understand every word of a contract before signing it. If you don't understand something, ask for clarification, and NEVER sign a contract with a service professional who makes promises that sound too good to be true.

-- Tips courtesy of HomeAdvisor.com