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A service history is the record of what has been done to a car, when and at what mileage. Nobody thinks about it until a mechanic asks when the timing belt was last changed, or a buyer asks to see the receipts, and by then the answer is a drawer full of paper and a guess. It takes very little to keep one properly. This guide covers what belongs in it, what can be left out, and a routine simple enough to survive a busy year.
Why it is worth the trouble
There are three reasons, and they are all about money or safety.
- Better decisions at the workshop. When the mechanic can see that the brake fluid was changed last year, or that the same fault came up twice, you pay for diagnosis instead of repetition. It is also how you notice a part being replaced again far sooner than it should.
- A warranty that holds. If you have a warranty or an extended one, the maker can ask for proof that the scheduled maintenance was done. A dated record with the mileage is that proof.
- A better sale. A buyer looking at two similar cars will trust the one that can show what was done to it. A complete history does not make a car new, but it removes the doubt that makes people offer less.
There is a fourth one that nobody mentions: you stop forgetting. Most overdue maintenance is not a decision to skip it. Somebody simply lost track of when it was last done.
What every entry should hold
For each job, the same few facts are enough. If you have these, you have what anybody will ever ask for.
- The date.
- The mileage. This is the one people leave out, and it matters as much as the date, because most maintenance intervals are measured in distance as well as in time.
- What was done, in plain words. "Oil and filter" is fine. "Service" is not, because it says nothing about what was included.
- The parts, when they matter: the oil grade, the brand of the tires, the battery.
- Who did it: the workshop's name, or yourself.
- What it cost.
- The invoice, if there is one, or at least its number.
Keep the jobs you did yourself as well. An oil change at home is as real as one at a dealer, and a note with the date and the mileage, plus the receipt for the parts, is what makes it believable later.
What matters most, and what can wait
If you are rebuilding a history from nothing, do not try to recover every car wash. Start with the items that are expensive or that protect the engine, because those are what a mechanic or a buyer will look for first:
- engine oil and filter changes;
- the timing belt or chain work, with the mileage, since a failed belt can destroy an engine;
- brake pads, discs and brake fluid;
- coolant and transmission fluid;
- tires, with the date and tread depth when you replaced them;
- the battery;
- any repair of a fault, with the code if there was one.
Your handbook's maintenance schedule tells you which of these apply to your car and how often. Those intervals come from the maker, and they beat any general rule you read online. Add the legal dates too, such as the inspection and the insurance renewal, since a buyer will ask about those as well.
Fault codes deserve a line of their own. If a scanner or a workshop gave you a code, write it down with the repair. A problem that comes back is far easier to solve when you know what it was the first time, as we explained in what to do when the check engine light comes on. Our list of OBD-II fault codes can tell you what each one means.
Paper, spreadsheet or app
All three work, and the best one is the one you will keep using. Each has a typical way of failing.
A folder of paper is simple and convincing to a buyer, and it is what most people already have. It fails because it cannot remind you of anything, nobody can search it, and a single spilled coffee or house move can end it. If you keep paper, write the mileage on every invoice the day you receive it, since many invoices leave it out.
A spreadsheet is free and easy to search, and you can make it as detailed as you like. It fails because it lives on one computer, it is rarely open when you are standing at the workshop counter, and it does not tell you when something is due.
An app is on the phone that is already in your hand when you pay. It can do the arithmetic and warn you when a service is coming up. It fails if the data is trapped inside it, so check that you can export everything before you trust one with years of records. It also needs to work where you are, and a workshop's basement often has no signal.
Whichever you choose, keep the original invoices for the big jobs. A buyer may want to see them, and a photo of each one takes a few seconds.
A routine that survives a busy year
The trick is to record at the moment of paying, not later. Later does not happen.
- At the workshop counter, before you drive off, note the date, the mileage, what was done and the price. It takes less than a minute, and the invoice is in your hand.
- Every fill-up or so, note the odometer. Knowing the distance you actually drive is what turns an interval in miles into a real date.
- Once a year, look over the list: what is due, what was skipped, and whether the invoices are all there.
That is all of it. A history built this way does not feel like a project, and after a few years it is worth more than most people expect.
Keeping it in OdoKeep
This is the job OdoKeep was built for, so I will say how it handles it and leave the choice to you. Each car has a maintenance log and plan: you record a service from a catalogue of jobs with its date, odometer and cost, and the plan counts down what is next by distance and by date. It works with no signal, and you can export everything or produce a PDF report for a buyer or a mechanic. Reminders before a service is due are part of the paid plan; the log and the plan themselves are free.
If you already keep records in another app or a spreadsheet, you do not have to start over: there are guides for importing them.
