To check if you can benefit from a claying session, there is an actual test you can do. Its called a baggie test.
Take a clear plastic sandwich bag (not a shopping bag) and after washing and drying your car, put your hand in this bag and rub it on the car. If you feel an even and smooth paint surface, your car paint is clean. If you feel it is not smooth, then clayying will be good. Normally after a year or so of driving, any car will benefit from clayying.
You can also search many videos on internet for better understanding.
///M - The most powerful letter.
