Comfort and Convenience
How much fresh air to let in divides people: one passenger wants a window cracked open, another finds the noise and draught unwelcome. Preferences follow habit and where someone sits, so it is worth settling early.
Safety and Driver Assistance
Anything that needs setting — mirrors, seat, route — is easier to deal with in a stationary car than at speed. Knowing where the hazard switch sits is part of the same preparation.
Multimedia and Connectivity
Long stretches often run through areas with weak mobile coverage, so downloading music or podcasts in advance is practical. If audio playback from a phone is supported, the playlist can be queued before leaving.