A lot of light fixtures have aluminum lamp sockets, and the bases of the bulbs are also aluminum. After several surprisingly difficult callbacks to replace burned-out bulbs that were frozen in their sockets, I’ve concluded that aluminum doesn’t make good threads. It galls and sticks, sometimes causing the bulbs to break when you try to extract them.
The solution is to use a lubricant to keep the bulb from seizing in the socket. Ordinary lubricants don’t work well. But antiseize compounds do the job just fine. Available at auto-supply stores, antiseize compounds are lubricants designed to keep nuts and bolts from corroding together in tough environments, such as exhaust pipes. A small amount applied to the bulb threads makes the problem disappear. It is so effective, it will protect the socket at least through the second and third bulb. But I never get called back to replace bulbs anymore.
Ed Storey, El Paso, TX