Deja Do is a repeating todo list: create template lists of what you need to take on holiday, remember to pack every morning before leaving the house, or copy to your backup disk. Then simply tick the items off a copy of the template as you go, and delete it when you're done. Set a reminder so you don't forget to look at the list in the morning for the important last few items!
Every time you need to complete that task, create a new list from the template. If you remember something you forgot, add to to the template ready for next time.