Start with the job, not the listing
Most buyers scroll listings by price and model before deciding what the car has to do. That's backwards. Sort yourself into one of three buckets first, because each points to a different shortlist. Commuter and errands: short repeated trips, tight parking, fuel or charging cost piling up daily. Optimize for reliability and low running cost, not horsepower; a small petrol or a used EV beats a thirsty SUV you'll never load. Family and distance: car seats, luggage, highway miles, the occasional long haul. Crash-test ratings, cabin space, and quiet cruising matter far more than zero-to-sixty. Enthusiast or utility: towing, off-pavement, or a car you actually want to drive. Here a specific drivetrain or trim is worth paying up for, and compromise hurts.
Get the bucket wrong and no amount of haggling fixes it. The person who buys a three-row SUV for a solo 12 km commute, or a tiny hatch the year before a second kid arrives, overpaid no matter how good the deal looked.
Read mileage and age together, never alone
A single number lies. Mileage signals mechanical wear; figure 15,000 to 20,000 km (about 10,000 to 12,000 miles) a year, so a five-year-old car at 75,000 to 100,000 km is simply average. Abnormally low mileage on an older car is a yellow flag, not a green one: seals, rubber, hoses, and 12V batteries age on the calendar even when the car sits, and suspiciously round-and-low numbers are the classic setup for odometer rollback.
Age drives everything the test drive hides: cracking suspension bushings, brittle wiring, rust in salt-belt climates, and whether parts still exist. Counterintuitively, a high-mileage highway car that ran warm on long trips is often healthier than a low-mileage city car that idled in traffic and never reached temperature. Service history is the tiebreaker. A thick stack of stamped, dated records beats a low odometer with no paper trail every time, no exceptions.
Drivetrain and fuel type set your running cost more than the badge ever will. Turbo-petrol engines are cheap to buy but live or die by timing-chain and belt service. Diesels reward steady highway distance and quietly destroy themselves on short urban hops that never burn off the particulate filter. For used EVs and hybrids, the battery is the engine: demand a state-of-health readout and check remaining battery warranty before you so much as glance at the odometer.
History and inspection come before money
Never buy on a seller's word. Pull a vehicle history report and read it for accident severity, flood or salvage titles, and odometer consistency across owners: Carfax or AutoCheck in the US, Encar and insurance accident records in Korea, the auction sheet and shaken history in Japan. A genuinely clean title with one careful owner deserves a real premium; pay it.
The best money you'll spend on the whole purchase is a pre-purchase inspection (PPI). Hire an independent mechanic, never the seller's shop, to put the car on a lift for an hour. It costs a rounding error against the price and routinely catches frame repair, hidden oil and coolant leaks, a clutch on its last legs, and EV battery fade that no test drive surfaces. If a seller refuses a PPI, you already have your answer: walk. On the drive, start the engine stone cold and listen before it warms, watch for blue or white smoke on first throttle, and brake hard once on an empty road to feel for pull or shudder.
The depreciation sweet spot
A new car sheds roughly 20 to 30 percent in its first year and about half within three. That curve is brutal for the first owner and a gift for the second. The 2-to-4-year-old window lets someone else eat the steepest drop while you still get current safety tech, the tail of the factory warranty, and a car that's mechanically barely run in.
Avoid both ends. A one-year-old car costs nearly new money for trivial savings, so skip it unless you find a specific discount. A car past 8 to 10 years or 150,000 km crosses into the zone where one timing-chain, transmission, or HV-battery failure can cost more than the car is worth. The honest exception is models with cult reliability reputations, which hold price precisely because they keep running; you pay more up front and still come out ahead over five years.
CPO vs dealer vs private
Three paths, three trade-offs. Certified pre-owned (CPO) is priciest but bundles a manufacturer inspection, an extended warranty, and reconditioning. It's the right default if you can't judge a car yourself or simply don't want the risk. A regular dealer sits in the middle: more selection and some recourse, but inspection quality is all over the map, so get your own PPI anyway. A private sale is usually cheapest by a clear margin because there's no markup, but every bit of risk and paperwork lands on you. Only take it when three things line up: a clean history report, a passed independent PPI, and a seller who hands over maintenance records without flinching.
When to buy
Used prices run on rhythms you can exploit. Most leases are 36 months, so lease-return waves dump clean, low-mileage three-year-old cars onto the market a few months after each big new-car buying season; more supply means softer prices on exactly the cars in the sweet spot. Seasonality is dependable: convertibles and sports cars bottom out in autumn and winter, while 4WDs and SUVs sag in spring and summer. Buy a car out of its season and you're bidding against far fewer people.
Stack timing levers for the deepest discounts. End of quarter, end of year, and fiscal year-end push dealers to chase volume targets, with December especially soft on negotiation. Model-cycle timing is the underrated one: when a redesigned generation lands, the outgoing version drops hard overnight because it suddenly reads as "old," even though it's the same car it was the week before. If you don't need a car this week, wait for the off-season plus a sales-target month, and track the price history on the product page so you can tell a real low from a listing dressed up to look like one. The worst time to walk onto a lot is bonus or tax-refund season, when every other buyer is shopping and the dealer holds all the leverage.