Product review (4 stars): Great Buy I continue to return to purchase
I've bought these multiple times, for several years. I usually recommend rinsing them off before first use as sometimes they smell "plasticky. I always change out the filter every 3-4 weeks. Sometimes I will rinse it in warm/hot water to extent the lifetime. Only because of it drying out on one side/top. Since it's not run 24/7. They also sell a humidifier bacteria fighter. I highly recommend as it will allow you to extend the length of the filter replacement.
4 of 5 stars because they keep creeping up their prices. I used to be able to get 3 for under $20