Serious question, with this rule, how long does someone need to own the vehicle before they are able to resell it? Just wondering.
This is one of those facts-and-circumstances questions. There is no line drawn in the sand.
First, what is your intent? Second, how likely can you achieve your intent? Here are some scenarios:
You buy the car intending to use it for many years. One week after you buy it, you die (sorry to be morbid.) Your survivors need to sell the car for financial and economic reasons. Clearly, you did not intend to die. I would have no problem claiming the credit on your final tax return.
You buy the car in the middle of a divorce. Two weeks later, the divorce is final, and you have to sell the car pursuant to the divorce proceedings. I would not claim the credit. The imminence of your divorce and the property settlement would prove that you quite possibly had no intent to keep the car, or a minuscule chance to keep the car.
You buy the car just after taking a new job making 3x the amount of money in your old job. One month after you buy the car you realize that you are working for the mob, and do not wish to continue employment with such a company. No jobs are available and you need the cash to look for employment and pay bills during your unemployment. I would claim the credit. Clearly this was unforeseen.
You buy the car on the speculation that you will be able to start a lucrative business driving celebrities around your home town of Atlanta. You do no due diligence before buying the car, thinking that your income will be ample to make the monthly strokes on the car loan. Upon buying the car, you determine that you have many hurdles to surmount to be licensed in Georgia to drive people for hire, including a $1,500 course to receive a special driver license. You need to get out from the debt on the car, so you sell it. Clearly, you did zero investigation before purchasing this car, so while your intent may have been sincere, it was unlikely that you could achieve it. I would not claim the credit.
While my stories are pure fiction, situations like these occur all the time with income taxation. In facts-and-circumstances cases, the burden of proof is always on the taxpayer. Once the taxpayer provides a satisfactory burden of proof, the ball then is in the taxing authority's court to challenge or accept.