Massage table warmer question?
A great deal depends on where you live - the time of year - temperature of the day - client preferences - etc.
That said, when I use my Sunbeam table warmer (BTW regular twin sized mattress types are mucho cheaper to purchase than the standard "pro" versions sold via massage supply houses) I turn it on in the AM to take the chill off the sheets. I have it under a sheepskin pad, so that you can't feel any wires.
Some clients love to be really warm, others prefer to be cooler. So whether I keep it on or not depends on them. I do find that most pregnant women I've worked on can overheat to easily, as can women who are dealing with pre-menopausal & menopausal hot flashes. Also some other people just tend to run hot, and so they don't want the extra warmth.
As for blankets the same thing applies, always check in with the client when they come in & perhaps part way through the session (if they are alert) to find out
if they are comfortable, being either to hot or to cold, etc.