Insurance for contractors covered 2

Insurance for Contractors: Do you have your back covered?

For some Contractors business insurance is a requirement from their Agency or a contract condition however, for others it comes as a choice as to whether or not to purchase it. As a Contractor (especially for those entering the contracting world for the first time) it may be a confusing topic as to whether or not to take out insurance if you do have the choice, and if so, which insurance?