My headlamp burned out on my Mini Cooper so I went to Auto Zone to get a new one. They ordered it because it isn't stocked. Before doing so, I asked if there was a possibility it could be under warranty. They said with confidence that it would not be because it's normal wear and tear like tires. I picked up the $108 bulb later that day and took it to the Mini dealer for installation. The dealer then notified me that the bulb they ordered was wrong and it actually was under warranty. I will be returning the bulb today for a refund.
I recommend having a better idea than I did of what you need before you go here.