The proverb "A good start is half the battle", certainly applies to video editing. Setting up your work environment and project to your needs is key to success. In setting up your video project, you have to distinguish between:
Work Environment related settings and activities:
These settings apply to all of your projects and are set at "Blender level"; for example the installation of add-ons. In fact, they can also influence your non-video editing projects. Most of these settings remain more or less stable throughout your projects and should probably only set once.
Project related settings and activities:
These settings vary from project to project and are very specific for your project; for example the output media format. For each new project, you have to evaluate these settings and activities.
Of course, many settings and activities occur at both levels. For example, automatic proxies can be enabled globally but changed on a per project or even strip basis. The layout of the Video Editing Workspace is defined at Blender level but can be tweaked per project.