Janelle Villaseñor of Golden Hill is an avid traveler. In fact, when she’s not traveling she is planning her next trip. She’s been to Japan, Toky, and Rome.

One thing Villaseñor learned on her recent trips is to declare to customs what she’s carrying in her suitcase.

“I love to go on trip,” Villaseñor told NBC 7. “That is my new hobby. I work to travel.”

One big incentive for buying abroad is duty-free shopping, which allows travelers to purchase products without paying local taxes. It’s important, though, to know the maximum amount you can declare, otherwise you can not only be fined but you could even have legal problems.

“There are limits,” Sally French, a travel expert at NerdWallet, told NBC 7. “You can’t just go on a massive shopping spree and expect that you won’t pay taxes on these things.”

The limits on the value of duty-free products that can be brought back to the United States depend on which country you are returning from. For example, according to U.S. Customs, residents returning to the States from Europe can bring in up to $800 per person in duty-free items every 31 days. For those returning from the U.S. Virgin Islands, American Samoa or Guam, the limit is $1,600.

Family members can combine their purchases, but the head of the family must declare all merchandise, French said. For any amount above the personal exemption, the traveler will pay a flat rate of 3% in taxes. 

Villaseñor recommends saving all receipts from tax-free purchases and having them organized to avoid delays at Customs.

“I’ve seen Customs ask for all their personal information,” Villaseñor said. “They keep their passports. Some people, I’ve heard, lose their connecting flights.”

Anybody who fails to declare tax-free purchases at Customs can be subject to sanctions, including confiscation of their overseas purchases.

“You spend so much and had such a good time and memories, you don’t want to ruin it and end your vacations on a bad note,” Villaseñor said. 

Anybody in the Trusted Traveler program with a Global Entry card who does not declare duty-free purchases when arriving at the airport in the United States runs the risk of losing them.