We are sorry your Febreze CAR didn't last as long as you expected. Our products undergo many quality checks to ensure they get to you with the best results, so we don't expect these things to happen. Although Febreze CAR is designed to last up to 30 days when it is on the low setting, this is an estimate. Other factors affecting how long it lasts include how high and how often the heat or air conditioning runs. Also, the scent will most likely last for less than 30 days if the intensity is high. The product is completely used up when there is no longer visible liquid in the device, and the scent is no longer noticeable. So we can help you get back to breathing happy, please call us at (800) 308-3279 Monday through Friday, from 9 AM to 6 PM EST.