Set a realistic budget for your door installation

Determining your budget will dictate the style, quality, and type of doors or windows you choose and will help you evaluate the bids you receive. When deciding how much to spend on installing doors, estimate what percentage of your income is actually available for the project and how much you may need to borrow.

I recommend: The National Association of the Remodeling Industry (NARI) has a worksheet to help you determine how much lenders are likely to approve for your renovations. If you plan to take out a loan for installing doors, estimate payments with a loan calculator like the one at Bankrate.com.

Find qualified door, window contractors

Finding licensed, insured, and bonded door contractors is essential to ensuring that your door installation meets all building codes and that the appropriate permits are acquired.

I recommend: Both ServiceMagic and Remodelers-Online provide referral services that allow you to locate qualified contractors in your area and request bids.

Verify that door contractors are licensed, bonded, and insured

Confirm that your contractor has General Liability Insurance to cover any damage that might occur to your property, Workers Compensation Insurance to cover the door contractor or any employee of the company who might be injured while working on your property, and Bonding to protect you if the contractor goes out of business or is unable to complete your project. Ask to see your door contractor's state or local contractor's license, Certificate of Insurance (or insurance company and agent's name), and Certificate of Bonding.

I recommend: The Contractor's License Reference Site connects you to your state's contractor license board. DoItYourself offers a similar service, allowing you to search for contractor license and registration information by region of the country.

Get at least three written bids from door installers

A good door installation bid should include a detailed materials list with specifications, labor costs, specific time frame of your project, and a payment schedule.

I recommend: HomeBlue provides free bids from door contractors in your area - usually within hours. Better-Door-Contractors.com offers 4 free estimates with no obligation to buy.

Get written contracts from door installers with explicit payment schedules

Starting your door installation project with a well-drafted contract can head off trouble later. It is important to settle on a schedule of payment. Beware of door installers who ask for full payment before the job is completed.

I recommend: The sample contract from 411HomeRepair.com shows the elements that should be included in your contract. The New York City Department of Consumer Affairs also has an excellent contract form that may be modified to suit your project.