I have had the first filter in for less than a month, hard to review at this time. Still have all the allergy symptoms, eyes, nose, etc. I love that they are a 1/2 inch below what the 20x24 says. A true 24 inch long filter sticks out of the front of my AC by about a 1/4 of an inch. This little bit makes your filters fit perfectly. If after the 2nd or 3rd filter, my allergy symptoms improve, you may have a long term customer, if not, well, we'll see.