I've boosted my financial security by keeping my old truck

Sometime soon, the odometer on my truck will hit 100,000 miles.

That might not seem like a big milestone, but surveys have found that many Americans trade in their vehicles long before hitting this mark.

But I'm just getting started.

I plan to drive my 2003 Nissan Frontier (you can see a picture of it and me below) for as long as possible -- certainly at least another five years and 65,000 miles.

Hopefully beyond that.

I will buy a new truck when reliability becomes an issue and I have to spend too much on repairs.

I'm not holding onto my truck because I'm broke. I’ve simply decided to forgo automotive luxury to boost my financial security.

Aside from a mortgage or rent, an auto loan might be a consumer's largest expense. And if you don’t make your vehicle purchases wisely, it can be a lifelong financial drag.

While a vehicle is a necessity in many parts of the country, it's a terrible, depreciating asset that has high costs and can be next to worthless by the time you get rid of it.

On strictly financial terms, you want to spend as little as possible on a vehicle and drive it as long as you can.

In a perfect world, you'd pay cash for your vehicle and not borrow a dime.

But that's not a possibility for most people.

The next-best step, depending on the interest rate you're paying, is to pay off your loan as quickly as possible.

I paid off the loan on my truck in 2007, two years sooner than I was required.

It's been wonderful not to have a car payment for five years.

During that time, that monthly payment, which would otherwise have gone to a lender, has been going to my Roth IRA, investments and a savings account I have set aside for a new vehicle.

I owe a fair part of my financial security to my lack of a car payment.

I consider my truck not just a thing to get around in but a tool that saves me money.

Because every day, week, month and year longer I drive it means more money in my pocket.

If I were to buy a new vehicle today, I'd likely end up with a $300 monthly payment based on the purchase price, my trade-in and down payment.

So the way I look at it, I'm saving $3,600 a year by continuing to drive my truck.

This doesn't even factor in the increased cost of my collision and comprehensive insurance for a new vehicle.

It is getting older and I do expect to have to put a little money into it. I'm going to need a new timing chain, a new clutch and possibly a few other repairs in the coming years.

But even if I factor in $800 for an annual repair budget, that's still $2,800 per year, or $233 per month, I'm saving.

And since I save and invest that money rather than spend it, those savings add up even more.

If I can earn a 6% average return on that $2,800 per year, that means in three years, I'll have an extra $9,500 put away.

When the time comes, I should be able to walk into a dealership and easily put down $10,000 to $15,000 on a new truck.

That means I'll borrow less, have less debt and will pay less in interest.