You've probably been warned a multitude of times to stay out of the central file. You may have even had this angry baby tell you off? When is it okay to work in the central file? Never...except...
Keep in mind, most of these examples should only be done while others are NOT working in local files!
Security Guard mode - You want to make Revit interfere with users who seem determined to delete or move important elements repeatedly. This can be done by checking out a specific workset like Shared Levels and Grids for example. Then when you STC you "refuse" to return the User-Created Workset. This should be done in the central file using a special username, different than the rest of the team like Super Admin for example. Keep in mind that this is merely a modest hurdle for an experienced user to get past but it should deter the average user enough to point out that they were getting in harms way.
Managing Linked Files - Linked cad files and Revit models have a way of "disappearing" when they are managed in local files. At issue is the assumption by Revit that a linked cad file or Revit model should not be loaded into other user's local files for them. Revit expects the user to decide when to load them. If these linked files are managed in the central file the changes to the central file are taken more "seriously" by Revit when others use STC to publish and acquire any changes to the project. Users should avoid using File Manage links in local files. Use Visibility/Graphics or Temporary Hide/Isolate to manage the short term visibility of linked data files instead. Naturally any such links that are not needed should be removed as soon as possible.
Making a new Central File - You can use Detach From Central (DFC) to create a new central file instead but it still involves at least selecting the original central file. If you don't use DFC then you use File menu > Save As > Click the Options Button and check the option: Make this a Central file after save. This dialog option:
Note: You can also use DFC on a local file.
Working by yourself - If you are the only person working on this project routinely and you just want to take advantage of collateral benefits of using worksets then you can just work in the central file. There is nothing wrong with working in a local file instead however and it is even a good idea as it gives you some additional redundancy should something go wrong with your network or computer(s).
Clean Up after Others - Sloppy workset use means lots of elements on the wrong worksets. It is easiest to clean up after everyone when nobody is working in any local files. Open the central file, borrow every workset and get to work.
[Tip: Check all four workset "show" check boxes, select any workset, then use keyboard combination CTRL + A to select All worksets, then click the Editable button.]
When you are done be sure to STC and return everything you borrowed.
Did I forget any? Lemmeno!