Your car is six, seven, eight years old. It starts every morning, it passed its last roadworthiness inspection, it has never left you stranded on the roadside. And yet the doubt creeps in. A colleague has changed cars, a neighbour mentions his monthly payment, the mechanic said a word about the timing belt. Should you keep it or replace it? The answer lies neither in sentiment nor in the dealer's advert. It lies in a simple calculation you can do yourself with your service book, your last workshop invoice, your insurance policy and your vehicle tax statement. This article gives you the method.
"Everything still works" is not an argument, in either direction
Two intuitions come up with almost every owner, and both are wrong.
The first: "it's worth nothing anymore, might as well keep it to the end". This confuses resale value with cost of ownership. A car that is worth little can still be expensive to keep if a major service is coming. And a car that is worth little loses almost nothing in value, which is precisely its main advantage.
The second: "you have to sell before it starts costing money". This forgets that the replacement costs money too, from day one. Its depreciation, its higher insurance, its tax, its tyres. A monthly payment is not an annual cost, it is one slice of an annual cost.
The only way to decide is to compare two figures built the same way: what your current car will cost you on average per year over the next two or three years, and what the replacement would cost you over the same period. No market figures here, every situation has its own. The method, however, is the same for everyone.
Annual cost of ownership: the five items
For each car, current or considered, add up five items. Each item is costed per year, then averaged over the horizon chosen, two or three years.
- Loss of value over the year. Watch the definition: it is the value today minus the value in twelve months. Not the purchase price minus the current value. What you paid seven years ago is spent, it no longer counts. Only the value you are still going to lose matters.
- Maintenance and foreseeable repairs. The annual service, plus everything the service book announces for the coming year. A later section comes back to this in detail.
- Insurance. Compulsory third-party liability, partial or full casco depending on the age and value of the car. The amount is on your policy.
- Cantonal vehicle tax. It depends on the canton and on the vehicle's characteristics. The exact amount is on your last statement; for a car you are considering, your canton's website (vd.ch for Vaud) lets you check it before buying.
- Tyres. A summer set and a winter set wear out over several seasons: count the annual share, not the price of a full set.
Two items stay deliberately out of the calculation: fuel and parking. They are identical or nearly so from one car to the next, unless you change the type of drivetrain. In that case, and only in that case, add them on both sides.
For your current car, every figure already exists somewhere: the service book, the last workshop invoice, the insurance policy, the tax statement. For the replacement, ask for an insurance quote and check the cantonal tax scale before signing anything.
Depreciation: steep at first, almost flat afterwards
A car loses value its whole life, but not at the same pace. The first years are the most expensive: the car goes from new to recent used, and that step is costly. Then the curve flattens. A seven-year-old car still loses value every year, but far less than a two-year-old car, simply because it has less value left to lose.
The consequence is twofold, and it often surprises people.
On one side, your current car costs less than you think. Its annual loss of value is small, sometimes very small. If the maintenance is up to date, it is a cheap car to keep.
On the other side, the recent car costs more than its monthly payment suggests. In a lease, the monthly payment covers precisely that rapid depreciation, plus interest. In a purchase, the depreciation is invisible day to day, but it is very much there and you will see it on the day you sell.
To understand where a value comes from and how a professional puts a figure on it, read what determines a used car's market value. And since the drop does not happen in a straight line but in steps, notably around certain mileage thresholds, the article on when to sell depending on age, mileage and season details those steps. No need to repeat them here.
The upcoming maintenance: the real variable
If the remaining depreciation is small, it is not what tips the decision. The major maintenance ahead is.
Every vehicle has heavy milestones: timing belt, clutch, gearbox, suspension, a set of tyres and the brakes in the same year, a roadworthiness inspection to pass again with work needed to get through it. These items do not come up every year, but when they do, they can represent a significant share of the car's value.
The method: list what is coming in the next twenty-four months. Not from an impression or a memory, but from the service book and the manufacturer's intervals, then from a quote requested at the workshop. Each manufacturer has its own schedule, there is no general rule.
Once the list is drawn up, separate two categories. What is partly recovered at sale: a fresh inspection, new tyres, a service done with an invoice. And what is never recovered: heavy mechanical work on an older car, which a buyer considers due and will not pay extra for. The article on which repairs really pay off when selling does this sorting item by item.
This sorting changes the calculation. Maintenance that is recovered is not a true cost, it is an advance. Maintenance that is not recovered is a net cost, to be put in full in the "keep" column.
Insurance, tax, tyres: what moves when you change
This is the classic trap in the comparison: you set the new car's monthly payment alone against your old car, and you forget everything that goes up around it.
Casco. On an older car, many owners have dropped full casco, and that is often rational. On a recent car, it becomes relevant again. In a lease, the finance company requires it in almost every contract. The premium depends on the vehicle's value and power: the more the car is worth, the more it costs to insure.
Cantonal tax. It depends on the vehicle, not on you. Changing cars means changing tax statements. Up or down depending on the drivetrain and the canton, but it has to be checked before, not after.
Tyres. If the dimensions change, your current winter set does not follow. That is a full set to buy again in the first year, often on larger rims and therefore more expensive tyres. That set is then amortised like any other, but it is an immediate outlay the monthly payment does not show.
No prices here, they vary too much from one vehicle and one insurer to another. The principle is enough: these three items almost always go up with a more recent car. Forgetting them skews the comparison in favour of changing.
The tipping point
Once both columns are filled in, the rule is simple to state.
Changing becomes rational in two cases. The first: when the foreseeable annual cost of the current car, meaning its small depreciation plus the major maintenance ahead plus the likely repairs, exceeds that of the replacement over the long run. Over the long run, not for a single year: one heavy year followed by three quiet ones does not justify a change. The second case: when a need has changed. Another child, a new daily commute, a move, a parking space that requires charging. There, the calculation takes a back seat, the car no longer matches the use.
Conversely, if the major maintenance is done and paid for, you are entering the cheapest period in the car's entire life. Depreciation is low, the big milestones are behind you, insurance and tax are known. Selling at that point means handing the buyer the years you have financed.
A reasoned example, without francs. Imagine a car whose current value is modest. Its annual depreciation is a small share of that value. A quote for the timing belt and the clutch arrives, which on its own represents a significant share of that same value, and which will not be recovered at sale. Over the coming year, the cost of keeping it rises sharply. But if you keep it for three years after that work, the average annual cost falls back to a level almost no recent car reaches. So the question is not "is this quote expensive", but "how many more years will I drive it once this quote is paid".
What the calculation does not say
A cost table does not decide everything, and it should not claim to.
Safety and driver assistance have progressed. Fuel consumption too. Comfort, pleasure, image all count, and there is no shame in counting them. But they go up against the calculated annual gap, not in its place. If the gap between keeping and changing is small, those criteria legitimately decide. If it is large, you should at least know it before paying it.
In the other direction, the cost of a breakdown on an older car can also be quantified: a car out of action, a replacement vehicle, a missed appointment. That risk rises with age and mileage, and it weighs more on someone who depends on their car every day than on someone with an alternative. Put it in the "keep" column, with an honest probability, not with a fear.
If you decide to change: sell first, buy next
The order of operations matters as much as the decision.
Start by finding out the real value of your current car. Not the prices shown in listings, which are asking prices, but the prices at which comparable cars have actually sold. If an inspection is coming up, see also why a recent inspection weighs on the selling price.
Then choose how to sell. The most expensive trap is buying the next car before selling the current one. Consignment sale, at your home or in the showroom, avoids ending up with two cars or none: how it works is detailed here.
Before signing for the replacement you have chosen, go over its five items one last time with the real figures (insurance quote, tax statement, tyres) and never the monthly payment alone. The leasing calculator gives you an estimated monthly payment, but that payment is one line of the calculation, not the calculation. To choose between cash, credit or leasing for the next car, the existing comparison details what each option changes in total cost, ownership and required insurance. And for a concrete idea of what is out there, you can see the vehicles available at the showroom.
If you are still torn between keeping and changing, the simplest step is to bring the question to the garage with your service book and invoices. With the documents on the table, both columns fill in within minutes, and the decision stops being an impression.
