So of course we're over packing. RB even has her own suitcase.
When planning your destination wedding assume your guests are going to forget something or at least need something while they're away. Some hotels will have a stash of toothbrushes and shaving cream available but what if they need hair gel or sunscreen or just batteries for an electric razor.
Check with your hotel about local amenities and give your guests that information in the guest room gift you're making for their arrival. You should include drug stores, doctors, babysitting services, car services and any other type of business that you think is important for them to know. Hopefully no one will need to refer to the list but if they do, they'll appreciate that you put one together for them.
