I've never tried reusing the filters. They are some synthetic material with a paper like consistency, and over time build up mildew. Iwash with soap weekly and change every 4-6 weeks. In bulk they run maybe $8 each. A season worth cost less than one month phone bill.
I leave it set to no more than 45% humidity. Enough to prevent dry throat but not enough to cause condensation problems.
I leave it set to no more than 45% humidity. Enough to prevent dry throat but not enough to cause condensation problems.

![[Hearth.com] Now she wants a humidifier...argh. [Hearth.com] Now she wants a humidifier...argh.](https://www.hearth.com/talk/data/attachments/112/112001-26adba7857999787822f15c27c804776.jpg?hash=nleC51hi8f)