Using these engine bay caps is easy. Just remove the old caps from your Subaru WRX or STI (2008 - 2014) and replace them with the new Billetworkz B - Series caps. Make sure to place them firmly in position for a proper fit. As for maintenance, since the caps are anodized or powder - coated, they are quite durable. But it's a good idea to clean them regularly with a mild automotive cleaner to keep them looking great. Avoid using abrasive materials that could scratch the coating. If you notice any signs of damage, like a crack or a loose fit, it might be time to check the cap and, if necessary, replace it. Also, always double - check that you're using the correct cap for each fluid reservoir to ensure the safety and proper functioning of your vehicle.