"FSH" is one of the most valuable — and most abused — abbreviations in used car adverts. Real full service history can add hundreds or thousands to a car's value. But the term gets stretched to cover everything from a complete main-dealer record to a glovebox containing one oil change receipt and optimism. Here's how to judge what a history is really worth.

What FSH Actually Means (Three Tiers)

• Full main-dealer history (FMDSH) — every scheduled service done by the franchise dealer, on time. The gold standard, and genuinely worth paying more for on premium brands where buyers expect it
• Full service history (FSH) — every scheduled service done, but by independent garages. Mechanically this can be just as good; a skilled independent often knows the marque better than a dealership's junior tech
• "Some history"/"serviced regularly" — translation: gaps. Sometimes innocent (an owner who did oil changes but lost receipts), sometimes not

Since most services went digital, many cars have online service records held by the manufacturer — ask the seller to show the digital record on the dealer app or portal, not just tell you it exists.

What History Is Worth in Money

• On a premium German car (BMW, Mercedes, Audi), full history versus none can move the price 10%+ — these are complex machines where deferred maintenance gets expensive fast
• On a mainstream car (Focus, Corsa, i20), the premium is smaller — think 5% — but a total absence of history still knocks confidence and price
• The specific big-ticket items matter more than the stamps: evidence of a cambelt/wet-belt change, gearbox service, or brake fluid changes is worth more than three routine oil services

That last point is the one buyers miss. A "full history" that shows the timing belt is two years overdue is a £500+ bill wearing a halo.

The Wet Belt Warning

A special mention for engines with oil-immersed timing belts ("wet belts" — notably some Ford EcoBoost and Peugeot/Citroën PureTech units). These need belt changes on schedule with the correct oil, and neglect can be terminal. On these engines, service history isn't a nice-to-have — it's the difference between a good car and a gamble. No documented belt change at the due interval? Price one in, or walk.

No Service History? The MOT Record Is Your Fallback

Service records can be lost, faked or exaggerated. The MOT database can't — it's recorded by the testing station, not the owner. While it won't show oil changes, it reveals the consequences of care or neglect:

• Advisory patterns: a caring owner's car shows advisories being fixed year to year; a neglected one shows the same items recurring and escalating
• Mileage rhythm: consistent annual mileage suggests steady use; wild swings or plateaus raise questions
• Failure quality: failing on worn consumables occasionally is normal life; failing on "oil leak — major" or corrosion tells a deeper story

This is exactly the analysis DriveSage's AI runs — it reads the full MOT history and scores how well the car has been looked after, then prices that into the valuation and the maintenance forecast of what's likely to need spending next.

The Practical Rules

1. Verify, don't trust: flick through the actual stamps/invoices and cross-check dates and mileages against the MOT record. Fabricated books rarely align
2. Price the gaps: missing history on a mainstream car is a negotiating point, not necessarily a dealbreaker — assume the big services weren't done and deduct accordingly
3. Never pay FSH money for "FSH" you haven't seen — "the book's at my mum's" means it doesn't exist until proven otherwise
4. On wet-belt and cambelt engines, the belt record IS the history. Everything else is secondary