What Happens If You Don't Drive Your Car?
A car that isn't driven doesn't simply wait for you. Up to two weeks, it's almost always fine. After about a month, the battery, tyres and brakes start to suffer. Beyond three months, it needs proper preparation or it will cost you money when you come back to it.
Here's what happens, and when, and what to do at each stage — whether you're working away for a few weeks, laying a car up for winter, or wondering if the second car on the drive is quietly dying.
The short answer
| Time without driving | What happens | What to do |
|---|---|---|
| Up to 2 weeks | Usually nothing | Nothing, unless the battery is old |
| 2–4 weeks | A modern car's battery can run down | Put it on a battery conditioner |
| 1–3 months | Flat battery, early flat spots on the tyres, brakes sticking, fuel starting to degrade | Conditioner, extra tyre pressure, handbrake off |
| 3–6 months | Battery damage, semi-permanent flat spots, rusty brakes, stale fuel, damp in the cabin | Prepare it properly, or store it |
| 6 months + | Tyres, fluids and seals ageing; mice and mould likely | Full lay-up, SORN, and a check before it runs again |
Up to two weeks: nothing to worry about
The RAC says leaving a car for up to two weeks "should be fine, with minimal risk to the battery, tyres, fuel, or fluids". The AA agrees: most modern cars with a reasonably healthy battery should last at least two weeks without being started.
The exceptions are a battery that was already weak, very cold weather, which reduces what a battery can deliver, and cars with power-hungry alarms or telematics. If your car has been slow to start lately, two weeks may be enough to flatten it.
Two to four weeks: the battery goes first
A modern car is never really off. Alarms, keyless entry, trackers and the car's computers all draw a small current around the clock. That constant drain can run a healthy battery down in two to four weeks.
A 12V car battery is fully charged at about 12.6 volts. Leave it below roughly 12.4 volts for long and sulphation starts permanently reducing how much charge it can hold. That's why a battery that has gone flat once or twice often never quite recovers.
What to do: connect a smart charger or battery conditioner. It holds the battery at full charge without overcharging it, and you can leave it connected indefinitely.
One to three months: tyres, brakes and fuel
After about a month, problems spread beyond the battery.
- Tyres develop flat spots. A car sitting still loads the same patch of each tyre constantly. For the first few weeks any flat spot is temporary and clears once the tyres warm up. Continental says tyres standing under load for a month or longer develop semi-permanent flat spots that normal driving won't remedy — the vibration on the motorway that doesn't go away.
- Tyres lose pressure. All tyres lose a little air over time, and the lower the pressure, the worse the flat spotting.
- Brakes rust and stick. A light layer of rust forms on brake discs overnight in damp weather and normally wipes off with the first few stops. Leave it for weeks with the handbrake on and the pads can bond to the discs.
- Fuel starts to degrade. The RAC notes that after a month fuel can start to form deposits in the lines and injectors. Standard E10 petrol absorbs water from the air, which speeds this up.
What to do: keep the battery on a conditioner, raise the tyre pressures (see below), leave the handbrake off and chock the wheels, and fill the tank, ideally with E5 super unleaded and a fuel stabiliser.
Three to six months: this is where it gets expensive
Past three months, a car left unprepared starts collecting repair bills:
- The battery is likely to be flat and possibly permanently damaged, unless it was on a conditioner.
- The tyres may have semi-permanent flat spots.
- The brakes may be seized, especially if the handbrake was left on.
- The fuel is going stale, and old fuel can cause rough running and blocked injectors.
- The cabin starts to smell damp. With no airflow and no air conditioning, a car sitting through a British winter can grow mould on carpets, seats and seatbelts — see our guide to car mould and condensation.
- Mice move in, especially in rural garages. They nest in air filter boxes and chew wiring.
At this point it's also worth thinking about the paperwork. If the car will be off the road for months, declaring SORN stops the vehicle tax and removes the legal need for road insurance, though it must then stay on private land. Our guide to laid-up car insurance explains how to keep it covered cheaply.
Six months and beyond: a car that needs recommissioning
Leave a car for six months or more without preparation and it needs more than a battery charge before it's safe to drive:
- Tyres age as well as flatten. Rubber hardens and cracks with time, whether or not the car is used.
- Brake fluid absorbs water over time, which lowers its boiling point and corrodes brake components from the inside.
- Rubber seals, hoses and belts dry out without regular use.
- The fuel may need draining if it has been sitting for many months.
None of this is inevitable. Prepared properly — battery conditioned, tyre pressures raised, handbrake off, stored somewhere dry — a car can sit for six months or longer and come out exactly as it went in. Our guide to storing a car over winter has the full preparation checklist.
How long does a car battery last without driving?
The honest answer is: it depends on the battery's age, the weather and how much the car draws when parked. As a rule of thumb:
- A healthy battery in a modern car: at least two weeks (AA), often three or four.
- An older or weak battery, or a cold spell: it can be flat within a week or two.
- A car with a lot of electronics: sooner, because the parasitic drain is higher.
How long do you need to drive to recharge it? The AA suggests a run of about 15 minutes, once a week, to keep a battery topped up. National Tyres suggests around 45 minutes of steady driving, ideally on a dual carriageway or motorway, to properly replenish a battery that's low. Short, stop-start trips with the heater, lights and wipers on can use more than they put back.
Should you start your car every week?
The AA's advice is that if you can't use a battery maintainer, running the engine for about 15 minutes once a week, or driving for 15 minutes or more, helps keep the battery topped up.
The catch is idling. A short idle on a cold engine produces condensation in the oil and exhaust without getting hot enough to burn it off, and it takes charge from the battery without fully replacing it. So:
- Best: a proper drive of 20 minutes or more, on the road, until the engine is fully warm, every week or two.
- Next best: leave it switched off and keep the battery on a conditioner.
- Least good: starting it and letting it idle for five minutes.
If the car is SORN'd, it can't legally be driven on the road, so the conditioner is the only option.
Flat spots on tyres
Flat spots form when a tyre stays in one position under the car's weight. There are two kinds:
- Temporary — from a few days or weeks of standing. You'll feel a slight vibration for the first few miles, and it goes once the tyres reach operating temperature and regain their shape.
- Semi-permanent — from a month or more under load. Continental says normal driving won't remedy these, and in bad cases the tyre needs replacing.
To prevent them, raise the pressures before parking up. Continental's guidance is +0.2 bar (about 3 psi) above normal for extended parking. For a lay-up of several months, many owners go further — up to about 10 psi extra — but never above the maximum pressure printed on the sidewall, and always reset them before driving. Rolling the car a few feet every couple of weeks helps too, and tyre cradles or foam mats spread the load for long-term storage.
Starting a car that's been sitting for months
Don't just turn the key. Work through this first:
- Look underneath for fluid leaks, and under the bonnet for nests or chewed wiring.
- Check the battery. Charge it fully before trying to start the car.
- Check the tyre pressures and look for cracking in the sidewalls.
- Check the oil, coolant and brake fluid levels.
- Check the tax, MOT and insurance — if the car was SORN'd, tax it and insure it before it goes on the road.
- Start it and let it idle briefly, watching the warning lights.
- Drive gently to begin with. Test the brakes at low speed; a few soft stops clear surface rust from the discs.
When a car should go into storage
If a car is going to sit for more than about three months, the choice is between preparing it properly where it is, and putting it somewhere that looks after it for you. Home storage works if you have a dry, secure garage with power and can check on the car every few weeks.
Managed car storage is worth it if you don't have a garage, yours is damp, the car is valuable, or you simply won't be around to keep an eye on it. A good facility keeps the battery on a conditioner, checks the tyres, holds the humidity down, and will notice a problem in week three rather than in April. See our guide to what car storage costs for prices.
Motorkeep is an independent introduction service for car storage; we don't own or operate any facility we list. Timings and figures are from the RAC, AA, National Tyres and Continental; your car's handbook is the final word on its battery, tyres and maintenance.
Frequently asked questions
- What happens if you don't drive your car for 2 weeks?
- Usually nothing. The RAC says leaving a car for up to two weeks should mean minimal risk to the battery, tyres, fuel or fluids, and the AA says a fairly healthy battery in a modern car should last at least two weeks without being started. Older or weak batteries may struggle sooner, especially in cold weather.
- Is it okay to leave a car for a month?
- It's the point where problems start. After about a month the battery can drain to the point it won't start the car, tyres can develop flat spots, and brakes can start to stick in damp weather. A battery conditioner, slightly higher tyre pressures and the handbrake off prevent most of it.
- What happens if a car is not driven for 3 months?
- Expect a flat or damaged battery unless it was on a charger, tyres with flat spots, surface rust on the brake discs, and fuel that has started to degrade. The car will usually start with a charged battery, but it's worth checking the tyres, brakes and fluids before driving.
- What happens if a car is not driven for 6 months?
- Without preparation: a battery that may never hold a full charge again, tyres that may need replacing, brakes that may have seized, stale fuel, and a real risk of damp, mould and mice in the cabin. With proper preparation or managed storage, a car can sit for six months and come out exactly as it went in.
- Is a 20 minute drive enough to charge a car battery?
- It helps, but it won't fully recharge a flat one. The AA suggests at least 15 minutes to top up a battery, while National Tyres suggests around 45 minutes of steady driving, ideally on a dual carriageway, to replenish it properly. Short stop-start trips can take out more than they put back.
- Should I disconnect my car battery if leaving it for a month?
- On most modern cars, a smart charger or battery conditioner is better than disconnecting. Disconnecting can reset alarms, settings and radio codes, and the battery still slowly self-discharges. Only disconnect if there's no way to charge the car where it's parked.
- Will flat spots on tyres go away?
- Temporary flat spots from days or weeks of standing disappear once the tyres warm up, usually within the first few miles. Continental says tyres left under load for a month or longer develop semi-permanent flat spots that normal driving won't remedy. Raising the pressure before parking up, and moving the car occasionally, helps prevent them.