You have to keep in mind that you should never use a humidifier when the relative humidity level is higher than 50 percent. In order to find out how damp is your room, get a moisture meter that will not cost you more than 20 dollars. You have to get your humidifier clean if its showing signs of mold or microbes infestation. Do not use a humidifier if you do not have distilled or demineralized water to fill in the bucket as you may end up spreading more contaminants. Finally, look for signs like constant musty mold smell or wood items started to decay.