Also, anything you bring back that you did not have when you left the United States must be declared. For example, you would declare alterations made in a foreign country to a suit you already owned, and any gifts you acquired outside the United States.

When entering the United States, you are legally required to declare all items you are bringing with you that were not in your possession when you left. This includes any gifts you received, items you purchased in duty-free shops, and items you "inherited" or found abroad. Specifically, you must declare all food products (fruits, vegetables, meats, seeds, and even some snacks), as many agricultural items are restricted to prevent the spread of pests and diseases. You must also declare currency and monetary instruments (including cash, traveler's checks, and money orders) if the total value exceeds $10,000 USD per family/individual. Failure to declare cash can lead to total seizure of the funds. Additionally, you must list alcohol and tobacco products; while there are duty-free allowances (typically 1 liter of alcohol and 200 cigarettes), anything over that must be declared and may be subject to tax. Declaring "commercial merchandise" (items intended for sale) is also mandatory. It is always better to over-declare than under-declare; if a Customs and Border Protection (CBP) officer finds an undeclared apple or a bottle of wine in your bag, you can face fines ranging from $300 to $1,000 and may lose your Global Entry or TSA PreCheck privileges.