Why do you need one? It’s not just because everyone else has one.

Did you know that most flooring manufacturers will void their warranties unless you use chair mats? That’s because without mats, rolling office chairs damage flooring surfaces. Chair mats protect flooring from indentations, scuffs and other marks, and from spills.

Chair mats also make it much easier to move within your workspace-it takes 80% less effort to roll your chair on a mat than on carpet. And rolling your chair around on carpet all day can cause back pain and leg strain.

Not to mention the static electricity carpet generates. An anti-static chair mat prevents static from reaching your computer or other electronic equipment, where it could cause you to lose data, or could damage your equipment ghostwriter.

Here’s how you select the perfect chair mat:

1. Flooring type

First, what kind of flooring surface will the chair mat cover? If it’s a hard surface, such as hardwood, laminate, vinyl or tile, you’ll want a mat with a smooth backing that won’t damage the floor and keeps the mat from moving. These mats are thinner and generally have straight, rather than beveled (sloped) edges.

If you have carpeted floors or any other type of soft flooring, choose a mat with small cleats on the bottom that are specially designed to hold the mat in place without damaging the carpet. If your workspace includes computers or other electronic equipment, it’s a good idea to buy an anti-static mat. The thicker your carpet, the thicker your chair mat should be. Thinner mats may bow or crack on carpets with thick pile and/or padding.

2. Size and shape

Then assess the space you want your chair mat to cover. Look at the total floor space, the width of your desk, the size of your chair’s base, and the area you’ll want to move around in. Chair mats come in standard incremental sizes and custom sizes are also available.

Many chair mats are rectangular. Others are single lip mats-rectangular with a lip that extends under your desk where you put your feet. There are also triangular, round and oval mats.

Be sure you measure carefully!

3. Color and Material

You can choose a clear vinyl chair mat so the flooring underneath is visible. There are also colored and patterned vinyl mats and ones made of Plexiglas, wood finish, glass, jute or sisal.

4. Price

Chair mats are available at different price points, with vinyl ones generally less expensive than wood-finish ones, for example. Vinyl is just as functional as wood when it comes to chair mats, so choose the type that fits your budget and preference.