Revit can be used for any Architectural task. Revit is software designed for architects and the things architects do.
Ultimately the decision of whether to Revit or some other software is based on the skills available to do the work.
Generally Revit is most efficient when:
staff prefer to use Revit for the task at hand;
there is a benefit from extracting data (e.g. measuring areas);
you need to test whether the design is achievable
MASTER PLANNING
Generally other 3D drawing software like SketchUp, Rhino or 3D Max are just as good at producing master planning documents as Revit.
If the aim is attractive drawings these softwares may be better suited than Revit (e.g. Revit is not very good at modelling terrain).
If there are a lot of areas to measure then Revit can be utilized for that purpose. Masses representing buildings can be imported into Revit for area measurements.
CONCEPT DESIGN
Revit is useful for producing basic floor plans and sections, along with area measurements, car park counts etc.
SketchUp, Rhino or 3D Max may be best for facades, particularly if they are free form. Regular facades (e.g. curtain walls) are best done in Revit. If the design is based on parametrics (e.g. same morphology, different breakups) then Revit Conceptual Modelling is ideal.
Free form elements can be modelled in SketchUp, Rhino or 3D Max and linked into Revit for visualization purposes (although they will appear very diagrammatic in plan and section).
SCHEMATIC DESIGN
Revit is best for schematic design as layouts can quickly be drawn that will appear in plan, section and elevations.
Although SketchUp, Rhino or 3D Max imports can be used for free form elements, modelling them in Revit tests whether they are achievable or not in the real world.
DESIGN DEVELOPMENT
In BIM Design Development is the beginning of documentation. It is vital Revit be used and the model be set-up to suit contract documentation requirements. Things such as as building orientation ('Project North'), project set-out, sheet size, drawing orientation and drawing numbering protocols need to be established.
If managed properly there should be no need to remodel a project between schematic design and design development.
CONTRACT DOCUMENTATION
Contract documentation is a continuation of design development. If Revit has not be used for design development it is too late to start.
CONSTRUCTION & AS-BUILT
There is no reason Revit can not be used for drawing production during documentation. Sketches can be created as required within the Revit model.
In any case contractors who use BIM will require the model to be maintained in an updated state for things like clash detection and programming.
Revit can produce CAD files if that is the As-built deliverables (in Revit it is effectively the same as printing). However many projects now require a model as an As-built deliverable which requires it to be kept up date during construction.