When you open a trip, its checklist shows what you planned to sort out for it. Anything still outstanding appears in a "Still to book" reminder near the top.

• Built-in items (flight, hotel, transportation, pet care, event) tick off automatically the moment you add a matching item to the trip's itinerary.
• Custom items you tick off by hand.
• Don't need something for a particular trip? Just uncheck it there — it won't count.

The type icons on your trip cards turn green as each one gets booked.