Review on Long-lasting MOVTIP Humidifier Cotton Sticks 🌬️ - Replaceable Wicks for USB Mini Humidifier (10pcs) by Brent Doolan

I change the cotton filter about once a month or when it looks dirty. The only thing about replacing the filter. DO NOT LOSE THE SMALL SPRING in the filter holder. Easily falls out when changing the filter. I unknowingly dropped it on the floor and replaced the filter without it, and the humidifier WILL NOT WORK without that little spring. Luckily I was able to find it on the floor, replaced it and now it's working great again!