Mechanical and Artistic approaches to 3D

Usually there are two approaches to the 3D modeling:
 

• Designers who need to create 3D models that have to be (as much as possible) dimension driven or commonly called parametric objects. We'll call this kind of approach the mechanical approach.
• Designers who don't care about future modifications to their models and that simply shape their 3D model in a more free-minded way. We'll call this approach the artistic approach.

There's not a pure dichotomy between the two methods; actually there are  a lot of mixed approaches.

The mechanical approach usually coincides with a fully constrained approach, which means that the designer has chosen to add all the possible constraints either in terms of Profiles, or assemblies and mating constraints.

Mechanical users who want a fully constrained 3D model need also to be aware of HOW they are placing the Work Plane.

On the other hand, in the "artistic" approach how and where constraints are placed is not important. "Artists" will keep their focus on the design intent, knowing that even in late situations, it will be possible to edit and fix constraints. See How to fix a parametric model by reassigning the Work Plane position to profiles.