After years and miles your cars interior will catch dust, dirt and all kind of filth inside upholstery. Once a while you should wash your cars interior to remove all of those from your sears and floor. Check out how I did it in my Volvo C30 with Karcher Puzzi – spray-extraction cleaner. If you keep you cars interior clean you don’t need to use air fresheners, it’s more healthy if you’re allergic, it looks and feels like a new car even in 10 years old car.