By Miles Nicholson
As a default, when you add new components into a schematic, the new components will assume the next available component tag irrelevant upon where you place the component in the set of schematics. If the design has not yet gone to manufacture, then of course you can do a Renumber Marks or Renumber Wires.
However when you are ready to issue a project for manufacture, you may wish to fix your component TAG’s, wire/equipotential numbers, cable numbers, terminal numbers, functions & locations to avoid the possibility of items being changed inadvertently after build has started or indeed completed.
If the marks of the items are set to manual, they cannot be changed automatically and therefore the project is effectively in an “as-built” state.