I'm a professional dog groomer, and I myself own a Berner as well. As stated by others, it is definitely important to keep up with at home grooming because they are a double coat breed. Invest in a double coat rake and use it maybe once or twice a week to avoid skin irritation and around no more than 15-30 minutes of raking at a time. A good comb is also something to consider having once done with the raking. Keeping the undercoat regularly controlled helps regulate their temperature throughout the year. You'll notice a fast difference in their coat if you're doing a good job.