How Long Do Spark Plugs Last?

Educational guide. U.S.-focused. Lifespan varies by driving, climate, maintenance, and vehicle design.

Modern iridium/platinum plugs often last much longer than older designs. Still, intervals vary by engine and driving style, and neglected plugs can cause misfires and damage.

Typical lifespan ranges

• 60,000–100,000 miles (≈96,600–160,900 km) for many modern plugs
• Older designs can be shorter

Why it matters

Worn plugs can cause misfires, poor fuel economy, and stress on ignition coils and catalytic converters.

Do it proactively

If you plan to keep the vehicle, proactive maintenance can reduce surprise failures and larger downstream costs.

FAQ

Do I need to replace coils too?

Not always. Replace coils if they test bad or are failing; many last longer than plugs.

Can old plugs cause catalytic converter issues?

Misfires can damage converters over time, so it’s worth addressing early.