Start with the paperwork, not the paintwork

It is easy to fall for a shiny bonnet on a forecourt in Gravesend, but the paperwork tells you far more about a car's real life than a fresh valet ever will. Ask to see the V5C logbook and check that the seller's name and address match where you are standing. If the car is being sold on someone else's behalf, walk away unless you are completely satisfied with the explanation. Check the chassis number on the V5C against the one stamped under the bonnet or in the door shut, and make sure the mileage recorded on recent MOT certificates rises steadily rather than jumping about.

A full service history is worth more than a low mileage. A car with 90,000 miles and a stamped book every year is usually a safer bet than a 45,000-mile example with gaps. Look for receipts for cambelt changes, clutches and clutches of work, not just oil changes. If the seller claims it has been "fully serviced" but cannot produce a single invoice, treat it as unserviced and price accordingly.

Before you travel anywhere, run a paid history check. It will flag outstanding finance, write-offs, stolen markers and clocking. It costs less than a tank of fuel and can save you thousands. If the seller refuses to give you the registration number in advance, that is your answer.

Rust, water and the Kent climate

Living near the Thames estuary means salt-laden air, and Kent's winter gritting lorries are generous with the rock salt. Both accelerate corrosion, so be thorough with your inspection.

• Check the wheel arches, sills, boot floor, spare wheel well and the seams around the rear number plate.
• Press the carpets in the footwells. Dampness here often means a leaking sunroof drain or a blocked pollen filter housing.
• Look at the bottom of the doors and around the windscreen rubber for bubbling paint.
• Check under the boot carpet and behind the rear lights — rear-end repairs are common and often hidden.
• Inspect the suspension turrets under the bonnet for fresh underseal, which can disguise a patch-up.

Panel gaps should be even all round. Run a fridge magnet wrapped in a cloth over the wings and doors; if it will not stick, there is filler underneath. Also check that all the tyres match in brand and tread depth, and look at the inner edges where Kent's potholed lanes and speed bumps do their worst. Uneven wear points to worn suspension or poor alignment, both of which cost money.

Inside the cabin and under the bonnet

Sit in the driver's seat and check everything works, one item at a time. Electric windows, all the lights, the heater on both hot and cold, the air conditioning blowing genuinely cold, the stereo, the reversing sensors and the central locking. A tired interior with a shiny, worn steering wheel and pedal rubbers rarely matches a claimed 40,000 miles.

Under the bonnet, with the engine cold, check the oil on the dipstick — black, gritty oil suggests neglect. Look at the coolant for a rusty brown colour, and check the brake fluid level. Start the engine and listen for rattles on start-up, particularly from the timing chain on some petrol engines. Blue smoke from the exhaust means burning oil; white smoke that does not clear means a head gasket concern. Let the engine idle and watch the temperature gauge. Then switch it off and check for fresh drips on the ground beneath.

Take a proper test drive

Insist on at least twenty minutes and make sure you are insured. A spin around the block tells you almost nothing. Start on a slow urban route through Gravesend or Northfleet, where you can test the brakes, steering and clutch at low speed, then head out onto the A2 or the M2 to see how it behaves at 60 to 70mph.

• Listen for whines from the gearbox and clunks over rough surfaces.
• Check the car tracks straight on a level stretch — if you have to hold the wheel off-centre, it may have been in a knock.
• Brake firmly from speed on a quiet road and feel for vibration through the pedal.
• Try a three-point turn to check the steering lock and any knocking from the front suspension.
• Take it over some of the rougher country lanes near Meopham or Cobham to expose suspension rattles.
• Engage every gear, including reverse, and check the handbrake holds on a slope.

If you regularly drive into London, remember that older petrol and diesel cars may now fall foul of the Ultra Low Emission Zone. Check the vehicle's compliance before you buy, not after.

Get an independent inspection

If the car is over a few thousand pounds, paying a local independent mechanic to inspect it is money well spent. They will get it on a ramp, check the underside, the brake lines, the subframe and the suspension bushes, and plug in a diagnostic reader for stored fault codes. Ask them to check for accident damage and to confirm the mileage.

Do not use a mechanic recommended by the seller. Choose your own, even if it delays the purchase by a day. If the seller will not allow an inspection, or pressures you to "decide today", walk away — there will be another car.

Budget for the first year, not just the price

A used car's asking price is only part of the cost. Before you commit, price up insurance for your postcode, check the road tax band, and look at what the next MOT is likely to need. Tyres, a cambelt, a clutch or a set of brakes can easily run into several hundred pounds.

Finally, agree the deal in writing and pay by bank transfer rather than cash where possible. Get a receipt showing the date, the price, the mileage and both parties' details. Buy with your head, not your heart, and a good used car will serve you well on Kent's roads for years to come.