Being aware of Demo or test drive vehicles. Manufacturers usually do their model year changeovers between August and November, but I've seen them do it as early as January. The rule is: they can release next year's models beginning on January 1. It can get confusing, but that's just how the industry works.

A vehicle is considered a leftover when the next year's models start showing up on dealer lots. It doesn't matter if the leftovers are still current-year vehicles.

Manufacturers start getting worried whenever too many leftovers pile up on the lots and end up competing with the new ones. Dealers need to make room for all the new inventory, so manufacturers tend to bump up incentives on the leftover models, especially towards the end of the year.

Does it pay to wait and buy a leftover model? It depends - sometimes dealers are able to sell the leftovers with ease; other times, they get desperate and are forced to slash prices. Usually, it's the latter, so in most cases, a leftover model should save you money.

However, you should be prepared to keep the vehicle for many years, so the depreciation doesn't outweigh the savings. A leftover is technically considered a one-year-old vehicle when you purchase, even if it's a current year model. Also, keep in mind the longer you wait to buy one, the more likely you'll get a better deal - but, you're also less likely to get the colors and options you desire. Leftovers are always part of a diminishing supply, so keep a close eye on the market to help you decide when to purchase.