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.
Some manufacturers claim the new LED bulbs will last up to 25 years under normal household use, but this is not proven. - Bulb breakage and bulb replacement costs have not been factored into this comparison chart. Incandescent bulbs and CFL bulbs are more easily broken than LEDs, which increases their cost of use.