Imagine you purchased a brand new home. Would you move all of the junk from your existing garage and attic into your new home? No. The same strategy applies to Box. Before you engage in a migration, understand the business case for keeping content rather than moving everything because you can.
When you get ready to launch your migration plan, make sure you provide ample training and support. Communicate to Box users what content should be migrated and how they should best accomplish that. If you would like a sample launch template, open a new ticket with your request.
Next: Content Migration - FAQ