If you have resource information duplicated in more than one project plan, a resource pool is an excellent way to collect resource information across project plans and spot problems such as resource overallocation.
Besides indicating individual resources’ nonworking time in a resource pool, you can edit the project calendar in a resource pool (for example marking holidays as nonworking time) and that information will be propagated to all sharer files of the resource pool file.
Resource assignment details from all sharer files are available for viewing (but not editing) in the resource pool file.
Consolidating project plans into a single plan is useful when you want to see all of the aggregate details in one place (the consolidated project plan), yet continue to work with the individual project plans (or allow multiple Project users to work with them).
When a task in one project plan has a logical dependency on a task in another project plan, you can link the two with a cross-project link. This produces what is sometimes called a ghost task (the predecessor or successor task) in both project plans.