Product review (5 stars): works good, they're cheap and worth the money for cleaning you have to do much less
I bought the Honeywell HWM450 humidifier at the beginning of January.  I use these and checked if it needed cleaning, and it hasn't been dirty enough to need it.  My previous humidifier, that I used without these pads cause I didn't know about them, got much dirtier and needed cleaning much more.  (both are warm mist types).  The beginning of March was the first time I needed to clean it, before that all I did was replace these pads when they were dirty, about 1-2 weeks, and the first time I didn't even replace it but just washed it clean.  That only seems to work one time then the pad starts to buckle and not fit good, but even if I didn't do that they're so cheap, they're worth it.  Seeing how they work, I wish I'd ordered more than 1 box of 12.  I'll be ordering them again.