You will receive a baggage declaration form to complete when you arrive in Bhutan. For tourists, the main purpose of this form is to ensure that you re-export anything you bring into the country. List any expensive equipment that you are carrying, such as cameras and laptops. Don't lose the form as you must return it when you leave the country.
Duty-free allowances include 1L of liquor. You can bring in only one carton (200) of cigarettes and these attract a 200% duty upon arrival. A packet or two is normally allowed in gratis. There are no restrictions on other personal effects, including trekking gear, brought into the country.
Departure formalities are straightforward, but you'll need to produce the form that you completed on arrival and may need to show all of the items listed on it. A lost form means complications and delays. If you lose the form, let your guide know as soon as possible so that special arrangements can be made to avoid any inconvenience.
The export of antiques and wildlife products is prohibited. If you wish to purchase a souvenir that looks old, have your guide clear it as a nonantique item with the Division of Cultural Properties, part of the Department of Culture inside the Ministry of Home and Cultural Affairs. Customs authorities pay special attention to religious statues. It would be prudent to have any such statue cleared, old or not.