Whether you are finally replacing threadbare carpeting or installing new carpeting for the first time, you have a lot of choices to make. That is why your most important decision is who sells and who installs your carpeting. You will need experts who are in the know and offer fair prices.

To identify top outfits, Twin Cities Consumers' Checkbook and Checkbook.org collected customer ratings of local stores and installers. Some stores were rated "superior" for the advice they provide by more than 80% of their surveyed customers.

But other area stores failed to get "superior" ratings from even half of their surveyed customers. Until Oct. 5, Checkbook is offering free access to its ratings of area carpet stores to Star Tribune readers via this link: Checkbook.org/StarTribune/carpet-stores.

Checkbook also collected prices for carpeting and installation — and found big differences for the exact same carpet. For one brand and style, Checkbook's shoppers received price quotes ranging from $2,050 to $4,568. For another, stores quoted prices ranging from $3,462 to $6,391. Before you buy carpet, consider the following:

Where will it go? Will you be eating or entertaining in carpeted rooms? Do you have pets and/or children? If so, get varieties with soil- and stain-resistant properties, and colors and textures that show dirt the least. For high-traffic areas, buy a low-density pile.

What is your budget? Carpet prices vary tremendously — from less than $2 to more than $12 per square foot. Charges for cushioning, installation and other labor often pad the basic price.

What styles and colors do you like? Since good-quality carpets last for years, choose designs, colors, and patterns that won't wear on you in the long run. Bring carpet samples home to see how they look in your space.

Which fiber? Nylon is the most popular carpet fiber, and it resists abrasion, crushing and mold. Olefin is popular for indoor-outdoor carpeting and in low-pile carpeting, and it resists static, soil and stains. It also repels moisture. But because it flattens easily, it's mostly restricted to low-pile carpets. Polyester is often used in deep-pile carpets because of its luxurious feel.

Check on density. Density is determined by the number of tufts per unit of surface area and the thickness of individual tufts. All else being equal, the denser the pile the better the carpet.

What pad do you get? Good padding minimizes carpet wear. It also creates a softer walking surface, insulates cold floors, absorbs noise, and makes irregular floors feel more even.

As a rule, the heavier the pad the better the performance. Checkbook gets a lot of complaints from carpet customers, so deal carefully with suppliers and installers:

Make a diagram of the spaces to be carpeted. Some stores take advantage of customers by supplying them a lot more carpet than they need. To avoid this, measure your spaces and make a diagram of the area. Indicate positions of doorways and closets and other protrusions.

Don't get floored on price. Although carpets from several major manufacturers are sold at most stores, it is often difficult to find the same style and grade on display at any two stores.

Price comparisons are possible, though, if the manufacturer's style name or number appears on the carpet label and you can find at least two stores that sell it. Contact several stores and ask for their installed price for that style and your choice of padding.

Tell salespeople you are calling several stores and give them one chance to bid.

Get bottom-line prices for the entire job. Price quotes should include type of padding, whether installation is included, whether takeup and removal of old carpet are included, whether installation of new quarter-round molding at the base of the woodwork is included, if you want it (usually an add-on), and whether doors that don't clear the carpet will be cut down (which many stores won't do).

Beware of special offers. The cost of "free" installation is often built into the price of the carpet.

You are likely to get a lower price for the carpet somewhere else where installation is not free. Also, beware of advertisements quoting prices by the room. The "rooms" are likely to be a lot smaller than yours.

Make sure the correct carpet is delivered. Some stores have taken advantage of consumers by delivering lower-quality carpet than the customer ordered, so make sure you get what you paid for.

If the store orders directly from the manufacturer, ensure your purchase contract requires the store to provide a copy of its factory invoice for the carpet, showing your name and the style, color and amount of carpet the factory shipped.

Check the carpeting and padding before it is installed.

Look for discolorations, dye spots, streaks, holes or yarn flaws. Also check to see if color or quality is significantly different from the retailer's sample.

Pay by credit card. If there is a problem with delays, or you receive incorrect or defective merchandise, paying by credit card gives you the right to withhold payment under the Fair Credit Billing Act and the policies of most credit card companies.

Twin Cities Consumers' Checkbook magazine and Checkbook.org is a nonprofit organization with a mission to help consumers get the best service and lowest prices. We are supported by consumers and take no money from the service providers we evaluate. See ratings of area carpet stores free of charge until Oct. 5 at Checkbook.org/startribune/carpet-stores.