I use it occasionally, when there is a sudden traffic jam, or a potentially dangerous situation. It's not every day, but certainly more common than the fog lamps (and I really don't want that to be less accessible either). In my old car it used to be a big button in the front of the console (not a Renault, but a Citroën). It was really easy to hit, which was great. When I need it is usually not a situation where I can take a second to make sure I am pushing the right button.