You are less likely to make dangerous errors, and if you do make such errors you have people close at hand to help out. You have the companionship of other witches with similar attitudes to yourself. In a good coven its members often become closer than family. It is easier to work certain types of magic in a coven than alone. Disadvantages of joining a coven.
Covens tend to make certain demands of their members.
For example most insist you be there for major festivals, and often for minor ones too. Some covens negotiate practices and decide collectively who will gain membership. Others do not. A few covens may carry out abusive practices. Finding a coven.