If you have studded snow tires they have to be off your car by May 1st by law. If they are regular snow tires there are a few advantages to changing them. One advantage is the wear, snow tires wear faster because there is not as much tire/tread on the road surface and mostly are made of a softer compound for better grip. Also snow tires have a more aggressive tread pattern and are usually noisier and can “sing or hum” as you drive. If you have what’s commonly referred to as all-season tires there is no need to change them because they are designed to give you service in all seasons as the name says.