They get enough exercise running about in your yard, or on long walks. They also get a lot of exercise playing about the house, especially if they have another dog or cat for a companion. Cardis are house pets and companion dogs, which means they are meant to be with you. This does not mean that you can't leave the dog outside in your fenced yard to play during the course of the day. You certainly can, provided that you have supplied water and shelter.
Dogs can be outside to exercise but brought in several times during the day.
Remember to take special care with hot summer or cold winter weather. Cardigans love to romp in the snow. They are adaptable to YOUR lifestyle. It is not uncommon for Cardigans to live as long as 15 or more. Average lifespan is about 12-15 years.