Ours would get done more often if I didn't have to get a step ladder out to reach them!! I hate knowing when they are dirty. I feel like I should't breath when they are dirty and on.
It didn't dawn on me to clean them during the winter. They aren't on very often then. :/
I'm guilty of seeing that and then choosing to just not look up. Every once in awhile I'll actually clean them but, by then, it takes a pillow case to catch all the gunk!
I never thought of using a pillow case for cleaning the fans. I used baby wipes. Since they are damp they trapped all the particles and it was easy cleaning.