How many km you drive and when your service is due

Where to find the service interval#

The interval is set by the manufacturer, not by the shop or by habit. You'll find it in a few places:

• The service book or owner's manual: the service schedule, with km and months for each step.
• The dashboard: many cars show how many km or days are left until the service, once the shop has reset the indicator.
• The invoice for your last service: some shops write on it the km at which they expect you next time.

If the schedule gives both km and months, what counts is the threshold you reach first. A car that does few km still needs a service after the number of months: oil ages even when the car stands still.

When the interval gets shorter#

Many manuals have two schedules: one for normal use and one for severe conditions, with shorter intervals. Check your manual to see whether you fall into the second. It usually covers:

• frequent short trips, where the engine never warms up properly;
• lots of city traffic, with constant stopping and starting;
• dusty or unpaved roads;
• towing a trailer or often driving fully loaded.

If you're not sure, ask the shop which interval they apply to your car and why. A good answer starts from the service book, not from a generic number.

How many km you drive a month#

Your monthly average is the number that turns a km threshold into a date on the calendar. Working it out is simple:

1. Note the km on the dashboard and today's date.
2. At least a month later, note the km and the date again.
3. Divide the difference in km by the number of months between the two readings.

The further apart the readings, the better the average: a month with a long holiday drive skews it, a whole year smooths it out. If the way you use the car has changed, say you've changed jobs, start a new average.

How to estimate the month of your service#

Take the km you need to reach, subtract the km you have now and divide by your monthly average. The result is the number of months until the service.

An example, with figures picked just for the arithmetic: your last service was at 60,000 km, the interval is 15,000 km or 12 months, and you're now at 69,000 km. That leaves 6,000 km. At 1,000 km a month, you'll reach the threshold in about six months. If the last service was eight months ago, the 12-month threshold comes in four months, so sooner: that's when you book.

Look at the dashboard now and write down today's km. It's the first reading you need to work out your monthly average.

Book two or three weeks before the estimated date. Good shops have full diaries, and a service done a little early beats one done late.

What to note after every service#

• The date and the km at check-in, from the shop's job sheet or invoice.
• What was changed: oil, filters and other parts, including the oil type.
• The next threshold: km and months, so you don't have to look it up next time.
• The paperwork: the invoice and, if you have one, the stamp in the service book. They matter for the warranty and when you sell the car.

A complete service history, with km and dates that add up, is one of the best arguments when you sell: it shows the car was looked after and that the km on the dashboard are believable.

When to go to the shop sooner#

The interval is for routine maintenance. Don't wait for the threshold if you notice any of these:

• a warning light comes on, especially the oil or engine light;
• the oil level drops noticeably between two checks;
• you hear new noises, feel vibrations or see stains under the car;
• the car uses noticeably more fuel than before.

How CariX keeps count of your km#

In the free driver account, every car has a “Mileage” section, with your readings in order and your monthly average:

• Readings come from several places: you add them with “Add reading”, a shop that works with CariX records them at check-in, you enter them with an expense such as a fuel fill-up, or you answer the monthly email.
• The monthly email asks “How many km is the car on?”. You answer with one tap, without signing in. You can turn it off in Settings.
• “Monthly average” shows up after two readings at least 30 days apart and is recalculated with every new reading.
• The estimated service date: after a service at a shop that works with CariX, your account shows the reminder for the next one, with a date and a km threshold. CariX estimates when you'll reach the threshold from your average and emails you two weeks before, but no later than the date on the reminder.

The estimate is only as good as your readings. If you stop adding km or your latest readings are very old, CariX stops guessing and reminds you on the date on the reminder.