I leave mine on for as long as I plan on sewing. I don't get a whole lot of time anyway PLUS, if I keep turning it off, then I lose any programming I did for the particular project I am working on, such as stitch length or whatever.

I have two 301's and a featherweight that I use all the time - they are all older than 50 years and have the original light bulbs in them and when I start to sew, they are one anywhere from 2-5 hours. They are still going strong.

I only turn my machine off if I am leaving the studio for the day. I always turn off my iron and unplug it as well when I leave the room if only for a short break ... our kitty likes to get close to the iron if she can...

Keep in mind the machines are not usually computerized; but when teaching classes especially children and teens, I had them turn off the machines whenever they got up from them to go iron, cut etc. It was a safety issue. I also reminded them to At home, sewing without students my iron and machines are on until I quit. However, if I have to go upstairs for any reason; I turn everything off on my way out because I have a tendency to get side tracked as well. hehehe Teresa

Turning any electrical equipment on causes the most wear. It's better to leave the machine on and turn off the light if you have a separate light switch, when using the machine every day.

It depends on the time frame, usually I sew everything I can sew at the same time, then get up and press everything. If I think it's going to be a fast press I'll leave it on, but usually it's 15-30 minutes at least so I'll turn my machine off. but I also have shoulder and back issues so I can't sew for the amount of time I used to-sadly.

If I am sewing something with a specialty or combination stitch I will leave it on all day if I need to get the project done so I don't have to re-program the stitch.
I would imagine that turning it off and on constantly can't be good for the light bulb.

I leave my industrial machines on, powering their big motors up and down is a big waste of electricity. The lights are separate and halogen, so they are turned off and on as needed. Been working for 30+ years for me.

I have a 37 year old White with the original bulb...this machine was used on a regular basis for years ...then set for almost 14 years/// i cleaned it and oiled it up and am using it on a more than regular basis again for the last 6 months...i leave the light on for hours at a time.

No help from here, either. I have a Janome and it "goes to sleep" if I don't get back to it quickly enough.