We had some sort of intricate computerised timing device on our previous cooker. I don't think we ever used it, but one day it developed a fault which tripped one of the switches on the board. Turning the electricity off to the cooker meant that the oven wouldn't light.
Two years ago, when we had a very heavy snow all in December, we were subject to a power cut lasting about 20 hours. Our heating wouldn't work and the cooker, which we had (probably very illegally) botched to bypass the electrics, was our only means of keeping warm as the temperature outside dropped to about -10°C.
We have since replaced the cooker for one whose only electrical gubbins is the ignition system and the oven light. This one has a clockwork timer but we never use it.