A trailer includes a lot of moving parts, but there are two you should focus on for regular maintenance. First, always make sure your tires are road-worthy. They should be inflated, rotated and replaced just like for a vehicle. And, second, make sure your taillights are always fully operational. Without functioning taillights, you put yourself and others at risk on the road. Naturally, there are myriad maintenance considerations when you own a trailer, but these two are first and foremost.