Every business needs liability insurance. This covers your business from damages or injuries caused to others.
Businesses can be sued when someone is injured or their property is damaged based on your being in business. You likely have heard of many people suing businesses because they were physically harmed by their product, or because they lied and it led to a customer's financial loss.
As a professional you are held to a higher standard than most people. Because of that and our litigious society business can be sued for a number of things by their customers as well as other businesses.
Different scenarios call for different types of liability insurance but the bottom line is that you need liability protection. It will protect you from lawsuits and help you cover legal fees associated with these types of problems.