So you go in to get an oil change, and the mechanic says you need new tires.

Do you really need new rubber? If so, what kind should you get?

The answer depends on several factors, including your car, how much you want to pay and what kind of driving you do.

While you may not think what kind of tires are on your car is important, remember that the tires are the only part of your car that actually touch the road.

"The truth is that your driving experience is only as good as the tires on your car," said Rick Brennan of Kumho Tire USA. "It is important to get the right tires so you get the safest driving experience."

The Basics

Before taking the plunge, take a good look at your current tires. If you're not sure you have enough tread left on your tire, start rummaging around your pocket for some change.

The most commonly heard standard for easily checking your tread depth is known as the "penny test." Turn a penny so Lincoln's head is pointing down and insert it into the tread. If the tread doesn't cover Lincoln's head, it's time to replace your tires.

However, Jennifer Stockburger, an automotive engineer with Consumer Reports, recommends grabbing some silver instead.

"If it covers up George Washington's hair (on a quarter), you know your tire won't compromise your safety," Stockburger said. "It gives you time to shop for your replacement before you need it."

When examining your tire, you should also look for uneven tread wear, flat spots and bulges or other damage to the tire's sidewall.

One Size Does Not Fit All

Now that you know you need new tires, it's time to learn what size tire you need.

Experts at the Tire Industry Association recommend that you buy tires with the same specifications as the ones that came on the car when it was new.

You can find those specs on a decal on your door frame, in the owner's manual or on the sidewall of your current tires. Sites such as TireRack.com can also help you find the right size by typing in the make, model and year of your car.

What you will get for your efforts will be an alphanumeric code looking something like this: P195/75-R14 89S. There's no need to crack the code (unless you want to). Just note it carefully for use when shopping.

And next you should consider what you want in a tire.

"The first step to selecting the right tires is to consider how they will be used," Brennan advises. "Consumers should think about how far and fast they typically drive, the weather and road conditions they encounter, how they want the vehicle to perform and look, how much money they want to spend, how long they plan on keeping the vehicle, and the weight and type of vehicle the tires will be mounted on."

Hit The Stores, Internet

In the past, the only way to comparison shop was to drive to each tire dealer or call them to get an estimate. Today, much of that can be accomplished online.

TireRack and other sites such as 1010tires.com can provide you estimates on tire costs and even ship them to a shop near you to have them installed.

But beware of those $19 tire offers often seen in the sports section of your local newspaper. While there are indeed tires available for that price, unless you are driving a Geo Metro or something similar, you're not likely to find new tires that low.

As Lauren Fix, host of DIY Network's "Talk2DIY Automotive" told Bankrate.com, you might be able to get better deals during two times of the year.

"The first is in April, which is National Car Care Month. Then in fall, specifically October, we have Fall Car Care Month," Fix said. "During April and October you can find promotions such as buy three tires, get one free."

Brand Name Versus Private Label

We've all been there. The tire dealer tells you they have a private label tire you've likely never heard of and you can save money by buying that one over the brand name.

Should you bite? The answer is most likely yes.

You might not have heard of the private label company, but it's most likely produced by a brand name you're more familiar with.

For instance, Goodyear also makes Douglas-brand tires for Wal-Mart, Bridgestone makes Cornell-brand tires for Pep Boys and Michelin produces Fisk tires for Discount Tire.

According to the Uniform Tire Quality Grading System -- which allows consumers to compare tire treadwear, traction performance and temperature resistance -- private brands perform as well, if not better, than many majors.

In addition, most private branders work very hard to keep their tread designs current with market demands. Because they also benefit from the design and technology of their manufacturer partners, private brands can also, in many cases, be considered just as advanced as name-brand tires.

Check The Warranty

Whether you are buying brand-name or private label, snow or all-season, or little tires for your compact or big tires for your SUV, what matters most is what you're getting for your money.

Be sure to check the warranty that comes with the tires when you are trying to make a decision, Stockburger said.

That $75 tire might offer an 80,000-mile treadwear warranty, while the $25 one may only be good for 35,000 miles. That's not to say the $25 is a bad deal. It depends on how much driving you do and what you want out of your tires.

When comparing warranties for two tires, it's also important to see if they are the same in terms of tread wear and percentage of credit for the new tire. You should also check to see if they come with a warranty against defects in workmanship and materials and that the tire dealer offers a nationwide warranty on its tires.

After all, having a limited warranty for a tire doesn't do you any good if you bought it in Massachusetts and need it replaced in Texas.