For lawyers, this includes dealing with risks such as obligations to non-clients who are parties to the joint defence contract. It is recommended that any common defence agreement should include provisions that should not be used as a basis for attempting to disqualify another Council. Commercial transactions, disputes and disputes often involve several clients with concerted interests, but with different lawyers. Clients and their advisors often want to communicate with other clients and consultants without risking renouncing existing privileges or immunities. Clients and legal advisers can benefit from the options developed by the courts, including through the common defence or the common interest. When reviewing the validity of a common defence agreement, courts generally focus on whether the interests of the parties are actually coordinated. For example, in a dispute with the Post-9/11 World Trade Center, the District Court for the Southern New York Region refused to recognize the common interest privilege invoked by the WTC leaseholders and the insurance broker`s staff who had obtained coverage for the WTC. JDAs can be written or spoken, invoked whenever lawyers (and their clients) speak to each other. However, if the CCM is not reduced to writing and then challenged by one of the participants, it will put the issue of privilege and legal work in the hands of a judge – this is not an ideal outcome.
Common defence relationships may exist between civil or co-accused parties and in a civil or criminal context. A common defence may even extend to non-parties, such as defendants` insurers.  The JDA can also be described as an agreement of common interest. Second, in such circumstances, cooperation between the accused is often not only in the self-interest, but also speeds up the trial or prepares for the trial. Co-counsel in multi-party cases often pool their resources in court; one lawyer may question one opponent`s witness, while the other may focus on another witness; One can deal with the opening statement, while another focuses on the sum. Entire parts of the defence or the continuation of a case may be divided between the parties. This division of labour not only helps the various parties on the same side of the case, it also promotes efficiency in the courts and prevents appropriate redundancy in interrogation and argument.