Before the recession hit, the median age for cars on the road was over nine years. And two-thirds had over 75,000 miles. We hear reports that those numbers continue to rise.

Many people are keeping their vehicles longer. The economy has influenced that, but the fact that modern cars and trucks are more durable and reliable means that owning a high mileage vehicle doesn’t have to be a painful experience.

Consumers with over 100,000 miles on their vehicles often ask how what service intervals they should follow. Let’s start with the special needs of the older vehicle.

The reality is that time and mileage will take its toll. The engine and transmission will have more sludge. The fuel, steering and brake systems will have gum and varnish built up. There’ll be more dirt and contaminants in the fuel tank. Corrosion and deposits in the cooling system. And seals and gaskets will start to dry out.

All of this, plus normal wear and tear, means that the engine might not be as strong as new so it just has to work harder to get the job done.

So we need to compensate. Consider high-mileage formulations for oil changes, transmission service, etc. These special formulations contain additives that condition the seals and gaskets to prevent leaks. They also have more detergents to clean sludge and other deposits. They cost a bit more, but they’re worth it.

In general, if a service was recommended every, let’s say, 15,000 miles when the car was new, you should continue to get the service done every 15,000 miles.

Talk with your service adviser about the condition of your engine. See if he thinks you should adjust your service intervals for oil changes or other auto maintenance to account for the older engine working harder.

Expect the oil filter to get dirty faster. Same goes for the fuel filter. And some leaks are to be expected so you need to keep a closer eye on fluid levels.

If anything, following recommended intervals is more important in a higher mileage vehicle. Skipping oil changes or other services can lead to problems much more quickly than with a newer vehicle.

So, have your auto service adviser help you with an assessment of your older car or truck. If you haven’t gotten around to a fuel system cleaning, or replacing power steering or brake fluid, a differential service or transmission service – it’s time to start taking care of those things. —It’ll help keep you on the road for many more happy miles.