That said, someone considering the two options has several things to keep in mind. Buying a car is often more appealing to those motorists who like to keep their vehicle for longer, rather than shopping for another every two to three years, acknowledged Hall.
And when you own, you don't have to worry about the miles you put on the vehicle. Leases normally set a cap on mileage, whether 10,000, 12,000 or 15,000 annually. Go above that and you could pay a significant penalty. The Swapalease analysis was based on the mid-range option, 12,000 miles a year.
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"If someone is going to drive a considerable more number of miles," the price for a lease would go up, and "would definitely close the gap," cautioned Hall. On the flip side, putting more miles on a vehicle, especially in later years, would also increase maintenance costs.
Another factor to consider: after years of holding below the rate of inflation, new vehicle prices have begun to rise, so that $30,000 vehicle could be more expensive when you go back to renew a lease in three years. On the other hand, costs are rising, in part, because manufacturers are adding new technology, so you could find a lot of new safety, comfort and convenience features.
That would be a potential plus for someone who goes with the option behind door number three, assuming someone else's lease. This is a fairly recent phenomenon, but gaining traction as more motorists choose to get out of a lease early. There are some additional charges, notably a lease transfer fee that, Swapalease estimated, runs around $600.
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But the savings here can be significant. The study focused on someone who would assume four leases during the same 72-month period, coming up with a total out-of-pocket expense of $37,040.70. That's $5,404.39 less than buying, and $2,630 less than a conventional lease.
Someone assuming a lease needs to be aware that they would be getting into a used, not new, vehicle, albeit one that might be only 12 to 18 months old. But the financial trade-off might more than make up for the lack of that new car smell.
—By CNBC Contributor Paul A. Eisenstein. Follow him on Twitter
@DetroitBureau or at thedetroitbureau.com.