I don't mess with the thermometer either; I do the same thing as Mike, I feel the outside of the lye container. I don't like to soap above 100 .. I like a slower trace. I don't even check on the oils ... just put them on low and when they're melted and the lye has cooled to the touch I just go. Again, as with everything soapmaking, preference.
EDIT TO ADD: I'm a bit of a liar .. when I'm using yogurt, heavy cream, or goat's milk I do religiously use a thermometer and do not let the mixture get above 90F.