Most modern cars need spark plugs changed roughly every 30,000 to 100,000 miles , depending on the type of plug and your vehicle’s make and model. Many newer vehicles with platinum or iridium plugs can go 60,000–100,000 miles or more before replacement, while older or cheaper copper plugs often wear out closer to 25,000–30,000 miles.

Typical replacement ranges

  • Copper spark plugs: about 20,000–30,000 miles.
  • Platinum spark plugs: around 60,000–100,000 miles.
  • Iridium spark plugs: often 80,000–120,000+ miles , sometimes up to the life of the engine in some designs.

Quick reference by plug type

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Spark plug type Typical mileage interval Notes
Copper 20,000–30,000 miles Cheaper but wears faster; common on older or budget‑oriented engines.
Platinum 60,000–100,000 miles Better durability; often factory‑fitted on many modern cars.
Iridium 80,000–120,000+ miles Premium, long‑life plugs; usually in higher‑end or newer models.

When to change them sooner

Even if you’re within the mileage range, replace spark plugs early if you notice:

  • Engine misfires or rough idling.
  • Hard starting or poor acceleration.
  • Noticeable drop in fuel economy.

Best practice

The most reliable answer for “how often should spark plugs be changed” for your specific car is the interval in your owner’s manual , which accounts for engine design, plug type, and driving conditions. If you tell your car’s year, make, model, and mileage , a more precise recommendation can be given.

Information gathered from public forums or data available on the internet and portrayed here.