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.
They wanted to know how long a standard string of Christmas lights should last before a bulb burns out. For this question, I contacted one of our main vendors. I was told that a standard string of Christmas lights whether it be a 50 light set or 100 light set should be able to last 1000 hours. We are talking about AC powered strands of light only.