These are useful, I have a 'blow r buddy' which is decent and also warms the air slightly, but it is overpriced for what it is and I would buy an alternative product with no "detailing" tax, if it needs replacing. But I only use it to dry the car if I need to apply a product after the wash and need a dry surface quickly. Otherwise, if you're just doing a wash, and you use an inline water filter, there is no need to dry it - blow or otherwise. An inline filter will pay for itself compared to using a blower each time and eliminates a job.