On your insurance they ask whether the car is for work or not. Classifying your car as "Occasional use" means you cannot use it to drive to or from work. If you use it to get to work and have an accident you may not get any coverage. Of course the savings are better the farther you work from home as the increased mileage means higher exposure to a possible accident. This is taken into account when calculating your premium. At least this is my understanding, if i'm wrong someone will likely pipe up.