When I had my machine serviced, the engineer told me how many stitches it had done, and how many hours it had been on, and how many of those hours I wasn't actually stitching!

I was horrified to find out that the hours not stitching were greater than those not stitching! I am more conscience of it now, and turn it off more often.

I find mine gets hot (from the light) if I leave it on too long - about an hour is my limit for walking away with it on. I do that if I'm in the middle of FMQ - I hate to turn off while that's in progress, mid stream, because the intialization means the needle comes up, and things tend to get unaligned. I just leave the needle down and the machine on, if I just need a quick break.

If I might not get back to it, I turn it off and unplug. I'm afraid I'll forget and it'll end up plugged in during a storm or surge. I do use surge protectors. If it's just for a bathroom break, etc, I don't shut it off, but I put the 820 in "Eco" mode with that button to the right of the line at the bottom of the screen. Supposed to conserve the light, I guess.

I turn it off when I am done sewing for the time frame.

a guilty party here...I've left mine on overnight. sometimes, simply due to CRAFT disease, others because I've made lots of stitching adjustments and it's easier to leave on. I will be bringing it in for a maintenance visit in January and will ask the mechanic about this.

My 10 year old Bernina has showed no signs of my inattention. It is plugged into a serge protector but I just turn off the machine switch when I am finished for the day or project. The only time I unplug is when we are away. Sometimes it has been left on for a couple of hours? I don't really know because if I leave it on (when another task comes up) I usually get back to it later or go by the room and seeing the light is on, I will shut it off. I don't worry about it being on for the machine, it's more of a waste of energy concern.
My main concern is....opps I think I left the iron on? I never have but I forget. Mine doesn't have the automatic shut-off but after reading about a fire with that kind, I will be more careful!

Always turn off the 539 and the Bicor. Only can unplug the featherweights and if I go to do that, usually end up sewing on them some more and walk away leaving it plugged in again. Never have unplugged the treadle sewing machine or turned it off.

if you are going to be gone from your machine longer than a few minutes (over 1/2 an hour you should probably go ahead and shut it off- if less than that leave it on-
if you just leave it on for long periods of time if nothing else that light bulb is going to burn out alot sooner than it would otherwise- and other electrical components-

My EE husband says it does not hurt the machine to leave it on, if you don't mind wasting power... and it does not hurt it to turn on and off...

I turn mine off when I leave my sewing room or if I am pressing or cutting for any length of time.