Will it burn out my curling iron if I leave it plugged in all day by accident?

If it happens only once in a while, the curling iron should not be damaged. However, if you leave it on frequently, you'll risk shortening the life of the iron. As a safety measure, and to prevent any possibility of fire hazard, unplug your curling iron after using it. Professional curling iron heaters are more durable than the standard curling iron heater.