When and how to declare your spends before going through customs

You had a great trip abroad, ate some incredible food, saw some amazing sites and purchased some excellent items to bring back home. You're heading through immigration and you see a sign for customs and declarations. What do you have to declare? What can you avoid declaring? What will it cost?

Good news: Declaring goods isn't complicated. But it does need to be done correctly or you'll risk hassle and fines. Here’s how to declare what you bought abroad.

We'll get into specifics in a bit, but as a general rule of thumb, anything you obtained abroad needs to be declared. Some examples include:

If you have a question about whether you should declare an item or not, it's always smart to do so. When in doubt, declare. Worst case, you've wasted a bit of time because you didn't actually need to, but that's better than the reverse where you end up in a bureaucratic morass and possibly paying a fine.

Read More: Headed out of town? Read these financial security tips first

One common way to avoid issues at the tail end of the trip is to register items with U.S. Customs before departure. That Swiss-made watch or expensive electronic device? It might be smart to hit up the local Customs and Border Protection (CBP) office to obtain and fill out a Certificate of Registration. If you forget and realize at the last minute, you can always register at the airport, too.

Perhaps you want to pick up some liquor, perfume or other items in the airport duty-free shop. Go for it. You won't need to pay the duty (read: tax) on these items, but you do need to declare them. And if you exceed $800 in value you will actually need to pay duty. Finally, if you bring more than one liter of alcohol (or two if at least one is produced in specific countries), 200 cigarettes, or 100 cigars, you'll be responsible for paying the duty on those products. Again, when in doubt, ask.

Traveling with cash is never a bad idea and you can bring an unlimited amount into or out of the country without paying any taxes or duty on the dough. You do, however, need to file a Currency Reporting Form if you have more than $10,000. That figure includes the combined worth of what you're carrying, so add up the cash, money orders, traveler's checks and other monetary instruments to get the total.

There is a laundry list of items that you simply are not allowed to bring into the United States unless you have specific permission. Some of these are obvious (firearms and abusable drugs, for example) while others (cat fur) might seem surprising. You can get a full list on the CBP website. Also be aware of ceramic tableware. While it's not prohibited, the CBP warns that "such tableware made in foreign countries may contain dangerous levels of lead in the glaze, which can seep into foods and beverages." The more you know!

Just as a thoughtful pre-travel process can eliminate headaches at the airport, so can some consideration about how to pack. It's smart to keep the receipts of anything you bought handy (also, remember to get receipts!), and knowledgeable travelers keep all the items they are going to declare in one easily accessible place. There's nothing worse than digging through your bag and looking for something you declared as a Customs official watches.

You did the work, purchased smartly, packed correctly, and declared your goods. That's the good news. The bad? You owe some money. No worries. You need to pay when you return to the U.S., but you have plenty of options for payment: American dollars, personal checks, money orders, traveler's checks, and more, including debit cards at some Customs locations. Welcome back. Now get home and enjoy your new stuff.