If you eventually plan to take all four parts of the exam, you can check all four boxes. After you pass one part of the exam you have 18 months to take and pass the other three parts. See the 18 month requirements below (How do I calculate the 18 months rolling window?).
Though you may not notice, as bulbs age they don't generate as much light as when they were new. That means your headlights may still work after five or six years, but they may not be as bright or illuminate as much of the road as they used to.
Spark plugs last a long time but they donât last forever. Most spark plugs have a factory service interval of 100,000 miles, though some may be as much as 120,000 miles. Long-life platinum and iridium spark plugs will typically last up to 100,000 miles or longer provided the engine isnât using oil or doesnât spend a lot of time idling. Replacing spark plugs at 100,000 miles can be troublesome on some applications.