It is not so that one is certain that one won't have to pay anything upon returning with an expensive object
they can always ask to provide proof of ownership before you left the country to return there and in case you can't do that they would ask you to prove how much you paid
"...Moving any valuable items – like musical instruments – across borders can be difficult and time-consuming. Customs officers abroad want to be sure that you will take your equipment with you when you leave their country,
and customs officials on your return will want to be sure that you have not acquired your equipment while overseas. If, in either case, they are not convinced, you may have to pay import duty on your instruments, or worse, the equipment may be impounded. Inevitably, it will cause considerable disruption and inconvenience for your whole group....."
Moving any valuable items – like musical instruments – across borders can be difficult and time-consuming. Customs officers abroad want to be sure that you will take your equipment with you when you leave their country, and customs officials on your return will want to...
sechristtravel.com