I leave mine plugged in and on all the time. It has the auto shut off and it is very quick to shut off, I think. I can hardly sew one seam on a dozen blocks without have to tilt it to turn it on again.
And, if I am ironing a big stack and basically keeping the iron in the flat position as my other hand lays out the next piece, it will shut off then too and I have to tilt it back up. It thinks that it has been left in the ironing position for too long without moving.