I would like to know exactly in what cases im obliged to create a new project and not using existing

[Karim Belhadj]

Hello team

Im reviewing jira administrator certefication , so i do not understand exactly when i will be obliged to create new project and not using existing project , and when i have to create project with shared configuration ?

I need some cases please 

Regards 

[Joe Pitt]

You're not going to get an answer for 'exactly when' or 'obliged' because like @Nic Brough -Adaptavist- and @Matt Doar said there are too many things that can affect the decision.  One of the most common reasons is users from group A shouldn't have visibility into issues from group B. 

[Nic Brough -Adaptavist-]

That is entirely up to your users and processes you are supporting in Jira.

You will want a new project when you want to track a set of tasks separately outside an existing project.  Consider most importantly the differences in the way you want to track (different issue types, fields, sets of users, workflow) and also think about versions and components (as they are separate for each project)

You share the configuration with an existing project if you want the people in the new project to work in the same way as the existing project you are sharing with.

[Matt Doar]

Another valid reason for a new project is when access to a project needs to change. Different permission schemes, project roles, issue security schemes.

And a reason that is not documented, so not in the exams, is that some admin actions start to time out when you have a large Jira instance and more than about 50K issues in a project.