Do you visit all your machines on a regular basis?
I am feeling guilty.
I "think" my machines might stay fairly happy if I just turn the wheel (by hand - if it's stored too far away to be convenient to an electrical outlet) twenty times a couple of times a year just to stir things up now and then.
The guilty part comes from - it's a bit of a chore to access some of these machines to do that. They are buried under other things or stuck away in some far corner with stuff in front of them. (In other words, they are not being used.)