If our 18-month planning checklist is the essentials view, this is the extended version — every item that ever lands on a destination-wedding plan, grouped into phases. It includes the destination-specific items (passport renewals, vaccinations, welcome bags, guest transport, currency considerations) that shorter checklists leave out.
Print it, screenshot it, or tick it off digitally. Cross items off as you go. Do not try to do them all at once; the phases exist for a reason.