Car speakers generally do not require much maintenance. It is important to keep them clean and dry, as dirt and moisture can cause problems. If you notice that your speakers are not functioning properly, you may want to check the wiring and connections to make sure they are secure. It is also a good idea to keep an eye on the condition of the speaker surrounds (the rubber or foam material that surrounds the speaker cone). If the surrounds are dry and brittle, they may need to be replaced. Other than these simple checks, there is not much else you need to do to maintain your car speakers.