Maui has a casual ambiance.  There’s no need to bring dressy clothes or jewelry.  Pack lightly, being sure to include T-shirts, shorts, a sweatshirt (the evenings can be cool), sandals, swim wear, hat, and plenty of sunscreen.  With the exception of the main dining rooms in the major hotels, all other restaurants will allow shorts/T-shirts for evening dinner.  Most lodging has laundry facilities, and this will certainly help with the packing.

Be sensible!  By taking a few simple precautions, you can make your vacation a safe and memorable one.  Lock your accommodation when you’re leaving for the day or before bed at night.  Keep your wallet in a secure spot, and be sensible about the amount of cash you have with you at any one time.  If your unit has a personal safe, be sure to use it.  Never leave your laptop sitting out in view of anybody passing by.  DO NOT leave valuables in your car.