Streamin, spoken like a true professional. After preparation is complete, there can't be anything more important, or a step that's the most significant than promoting adhesion. The primer is, after all, the foundation for any good-great paint project. Testing that theory, and after the paint is fully cured, try pressure washing your project! The pressures WILL find the smallest of areas that indicate poor adhesion (poor preparation) and need to be repaired if you shortcut any areas.
The preparation is a long, involved task...but justified when the project is completed.
Mark