To buy the last of a particular model, or the first of a new design - for many buyers it's an agonising question. Catherine Cronin has some background for the argument
Side-by-side on a forecourt, two four-door, five-figure shiny saloons, squat aggressively beside each other; one is newly-launched with modern curves, fresh and futuristic styling, the other familiar, with a well-known history, a run-out model just being replaced.
Shortly after a new-car launch, the run-out model and its generally hipper latest version can find themselves on the same lot. So which to choose?
For many, there's no decision - they bypass the run-out in favour of the latest kid on the block.
Nevertheless, for some savvy buyers it's an opportunity for value and to the naked eye, all that's missing is the re-worked styling.
The decision can boil down to the best deal that can be secured on the day with the dealer, so buyers should be geared up on all of the factors before entering the showroom, says Eoin Lynam, marketing director of GE Money, publishers of a used car price index.
Their latest study suggests that if depreciation is the most important criteria when buying new, the replacement model would be the choice: it depreciates more slowly than the run-out.
But it's also important to look at the class of the car. In the case of the supermini, the difference in the speed of depreciation between in the new and the run-out was insignificant.
Executive cars tell a very different tale. Over four years, they showed the largest differential in depreciation between the previous and replacement models.
But other factors muddy the waters. Manufacturers tend to "spec-up" run-out models by including a host of features from the options' list free. The longer-term benefits of buying the latest version can be diluted heavily or indeed reversed when free extras in the run-out, such as air-conditioning, alloys, leather or metallic paint, are taken into account, says Lynam.
And it doesn't stop there. GE's study found that on average the run-out models were 3-4 per cent cheaper than their replacements. But these prices don't reflect the additional discounts often found on the run-outs, says Lynam. "And significant stockpiles could take the price of the run-out to 5-10 per cent less than that of the replacement car, making it very compelling."
Emotions can take over, and things like image and style have a big impact. Some buyers prefer the look of the new and some will want to stick with the tried and tested style of the old.
"It would appear that those who buy executive models like to buy the newest versions," notes Lynam.
Executive cars cost more to start with and depreciation is important, but buyers may also be more concerned with image than supermini drivers who are more likely to have chosen their car based on its ability to get from A to B, he contends.
In four years, the replacement models lost a little over half their value, about the same as the run-out supermini, while large family and executive run-outs were worth nearly two-thirds of their original price.
The biggest proportion of the hit was in the first two years, where replacement models lost one-third of their value while the run-outs lost about 37 per cent. In the next two years, replacement models lost another 20 per cent of their original value, while large family and executive run-outs depreciated by a further 26 per cent.
Because of this, buying the old model to tie you over for a few months until the new model arrives may prove an expensive option, says Lynam.
The GE Used Car Index tracks changes in used car prices. It includes superminis like the Fiesta and Corsa, large family cars such as the Avensis and the Primera, and executive cars like the 5-Series and the Mercedes E-Class.
Prices are for the mid-level specification model in the range, sourced from Motor Trade Publishers, producers of the motor-trade's reference book on used car values.