Thus, when I noticed only one light come on in my garage, I decided that I would replace both bulbs this time and upgrade them while I was at it--my low beams have seemed dim since I made the first replacement. With that in mind, I stopped by Freddy's after picking up Trevor, consulted the electronic guide, and was thrilled to see that the two-pack of the bulbs I wanted were even on sale.
The edge of that thrill came off when I got home, tried replacing the first bulb, and realized that I had bought a set of high beams (which I am keeping since they were on sale, and those bulbs are due to go out any time now). Grumbling, I returned to Freddy's, got the correct bulbs (which were not on sale), and returned home.
The first bulb came out easy (for me, I had Trevor practice with taking it out and he to make multiple attempts--hence the practice) and was easy to replace. The second one was a pain to replace as the cord was too tight to fit the bulb in correctly. Instead, I placed the bulb in its socket and then plugged it in, but only after trying to do it the other way for a while (which was difficult because the socket is in a place that cannot be easily seen and required me to feel my way).
At least my lights are working again, and noticeably brighter ... just in time for summer driving.