Some swear by it, and think of it as a must-have protector for their classic car or boat that prevents the fuel in the tank from converting into harmful, sticky, gummy resins destined to clog your carburetor as the thing sits in the garage over the winter.

Others are quick to claim it’s snake oil — nothing but a placebo to make motorists feel better about storing their vehicles away with gas in the tank. Either empty the gas in your tank, or just leave it in there without treatment and you’ll be fine anyway, the naysayers say, there’s no need to buy a product like Gold Eagle’s STA-BIL Fuel Stabilizer or Lucas Oil’s Fuel Stabilizer.

Ask Matt Irvine, an account executive at Lucas Oil, about this debate and he’ll say it’s just not worth the risk to skip on fuel stabilizer. Just one bottle of Lucas Oil’s product, which costs about $12, can treat 80 gallons of fuel, he points out.

“This stuff isn’t very expensive,” he says. “But to have someone rebuild your carburetor is about $300 to start.”

Understanding the truth starts at understanding what fuel stabilizer is at a chemical level and how it interacts with your gas. Unless you aced your senior-level chemistry courses in high school and remember the difference between a benzene molecule structure and a hexane molecule structure, it can be a bit intimidating to make sense of what’s in fuel stabilizer. But all you really need to know is that fuel stabilizer can be broken down to two basic components that act like a protective layer for the fuel in your tank.

Take Lucas Oil’s product for example: according to the product’s MSDS sheet it’s composed of 50 to 60 percent hydro-treated heavy paraffinic distillate and 25 to 35 percent solvent naphtha.

That first one sounds like a mouthful, but essentially it’s just a type of petroleum product, like kerosene. Naphtha is a petroleum product, too, one of the heavier fuels that results from raw petroleum processing.

Of course, Lucas Oil won’t give away its exact secret formula. But it’s clear fuel stabilizer acts as a protective coating for the gasoline in your tank by chemically bonding with it. It prevents the evaporation of fuel to avoid formation of those nasty, carburetor-busting resins, and also lubricates everything to stop sticky deposits from remaining behind in the tank.

“Fuel stabilizer really is a series of lubricants and antioxidants. It slows down evaporation rate and it tries to keep water away,” Irvine explains. While “the big lubricant and antioxidant is the paraffin part,” naphtha “will give the bang back to the fuel.”

Most drivers just don’t need to use fuel stabilizer. They put gas in the tank, start driving, and burn it up long before it ever starts to break down in a way that’s harmful. But once you have gas that’s going to sit in a tank for three weeks or more, it’s a good idea to add fuel stabilizer, Irvine advises, especially if you’re dealing with an older car.

More modern vehicles can compensate for degraded fuel with advanced fuel delivery systems. But recreational vehicles without variable ignition timing and variable fuel delivery are different — they’ll be the most affected by fuel degradation.

Products like STA-BIL and Lucas Oil will preserve fuel for 12 months based on regular dosage, and doubling the dosage could prolong storage time for up to two years, according to Golden Eagle’s website.

Most modern fuel has some ethanol in it, now, an additive that comes with its own corrosive consequences and water-attracting qualities. Both Lucas Oil and Golden Eagle have products specifically designed to deal with ethanol fuel.

“Ethanol is probably the biggest worry for fuel,” Irvine says. Classic car owners are especially advised to treat against these issues.

When it comes time to choose a fuel stabilizer off the shelf, don’t be tempted by the cheap stuff, he adds. Fuel stabilizer is a “you get what you pay for” product and it’s best to spend a few more dollars to avoid the grief caused by a busted carburetor.

Follow the directions on the label for best results.