I've been watching some cooking shows, and they seem very keen on there thermometers. They have prob thermometers, oven thermometers, meat thermometers, confectionery thermometers, oil thermometers... (Possibly these are all the same device, I don't know anything about kitchen thermometers).
Only thermometers I ever saw in real life, was my mother's roast thermometer (and I've made plenty of roasts without owning one), and her confectionery one that I broke as a child (and I've made plenty of toffee, with just the cold water test.)
So I've got on for quiet a while without owning one, and I've never seen one (out side of TV) used to check the oven temperature, or the oil temperature.
I'm wondering what the big deal is? Will using the right temperature change my cooking? Am I perhaps doing something unsafe in using any of the many methods for estimating temperature?