Used car values are volatile things, sensitive to economics, demand and even taste. There’s not much you can do about interest rates, but choosing wisely from the options list means your car will be worth more when the end comes as well as making your car more pleasant to be in until then. Here are the key things to look at before signing on the dotted line.

A crucial decision this, and one which probably gets more thinking time than any other. What seems perfect to you may be anathema to the general public, so beware of wackier shades. However, some cars are best in brighter colours than others. As a general rule, smaller cars tend to be more popular in more obvious hues as they are more popular with younger buyers.

As you move up the price scale, metallic paint becomes a default option, as does more sober hues. For a shortcut to the right colour, take a quick glance at used car ads and seen what’s most popular.

Even the humblest of tin boxes can be specified with air-con these days, so if it’s not standard, seriously consider stumping up the extra cash. As the standard specification increases, the decision of whether or not to upgrade to climate control rears its head.

This all depends on the make and model of the car: a humble supermini with a generally low-spec will not benefit from full-on climate, whereas a premium-targeted small hatch that already has a decent stereo and nice alloy wheels would be complete with distilled Arctic breeze fitted.

Everyone has heard or used sat-nav these days, so the question of whether or not to take the plunge is less of a dilemma than it was. In-built systems have distinct advantages, not least that the more modern system are usually bundled with Bluetooth phone connection and a smart audio system, which makes them even more desirable.

The alternative is of course a portable system, but as that won’t be going with the car when you sell it, think twice about getting any add-ons which require drilling or will leave marks in the dashboard. A portable system is cheaper but is essentially disposable as it ages, whereas an in-built system that costs more but will earn you more of a return come sale time.

The S word has always been of interest to buyers, not least since the introduction of EuroNCAP, but it’s also something that buyers are notoriously reluctant to spend their own money on.

However, most people have come to understand the benefits of ABS and airbags, so hopefully choosing an ESP at purchase time will become more of a draw as time goes on. An active rather than passive system, it has the ability to aid the prevention of an accident, and could arguably do more to save lives than anything else. Manufacturers tend not to seek a profit from this option either, so if you have your sensible hat on and the lives of you and your family are important, only think once about ticking the box.