Vehicles are expensive and many of us would like them to last longer. It's estimated every additional year you can keep a vehicle on the road you could save as much as $3,000 to $4,000. There are different approaches to rust proofing but some methods work better than others.

The Canadian Automobile Association recommends the oil spray method if you want to try and keep your car in pristine shape.

"We would agree that an oil based product should be applied every year for maximum protection," says CAA Technical Advisor Paul Datzkiw.

The oil spray is applied to a vehicles underside as well as inside doors and fenders. It has a creeping agent which allows it to seep into seams and other hard-to-reach areas.

Krown Rust Control sprays about 250,000 cars a year in Canada. Krown President Freeman Young says it's no longer just salt on the road that causes corrosion.

"Municipalities are also using magnesium and other chemicals on our roads to keep them from being slippery. They are also adding things like beet juice to help make them stick. These chemicals not only stick to the road -- they will stick to your car too," CAA Technical Advisor Paul Datzkiw says. 

The cost to have a car oil sprayed is $120 for a car and $140 for a van or SUV.

While many consumers have their vehicle sprayed in the fall or winter, Young says the spring is the best time to have the procedure done. He says "this is when a lot of the salt and corrosive chemicals are on your car and the spring is a good time to have the rust proofing oil applied."

Many car owners are concerned about the oil spray process because holes are drilled into a vehicle's fenders, doors and other areas but CAA says that it's the best way to get the creeping spray into all of a vehicle's nooks and crannies.

There are electronic rust control devices for sale on the market. Some car dealers have been selling them for as much as $800 or they can be purchased in automotive supply stores for as little as $150. According to CAA -- and those in the oil spray business -- electronic devices offer limited protection and are not recommended.

You can also have a tar based product applied to the undersize of your car. This is often offered when a car is new and is done at the dealership.

"The tar type spray applied to the underside of a vehicle does offer some protection and can also make a car's ride quieter. However, over time water can get in behind the tar based product and corrosion can take place," Datzkiw says.  

Rust proofing is most recommended for those living in Central and Eastern Canada. In Western Canada salt is not as widely used on the highways as it not as effective in extreme cold. It is also not used in the much warmer climate of British Columbia.

No one wants to spend money they don't have to. But having an oil spray application can make your car look better overtime, help keep your repairs down and could make your car worth more at resale.

Many companies with fleets have their vehicles oil sprayed, seeing the value in fewer repairs. If you don't want to have your car sprayed every year -– it can be done every other year. If you drive during the winter where salt and other chemicals are used on the road, having it done at some point could help keep your car looking better and running longer down the road.