Two Weeks Before
Book your service 2 weeks before departure. This allows time for: the mechanic to identify and fix any issues, ordering parts if needed, and a follow-up check if repairs were done.
What to Request
Tell your mechanic you're planning a long trip. Request: a comprehensive safety check (in addition to standard service items), brake inspection, tyre condition and alignment check, cooling system pressure test, battery test, and a check of spare tyre, jack, and wheel brace.
Why Not the Day Before
If the mechanic finds an issue (worn brakes, a leak, a bearing starting to fail), you need time to get it fixed before your trip. Discovering a problem the night before departure means either delaying the trip or driving with a known issue — both bad options.