Here is the page I described previously. I've pasted the contents below.
https://help.cbp.gov/s/article/Article1648?language=en_US#:~:text=Articles exported from and returned,with this category of goods.
I agree with you that it is unreasonable. According to this document, you must fill out form 4455 and bring the item in person to the CBP so that they can inspect it before you send it for repair. Then the person returning the item to you must include a copy of that signed form, along with various other specific information about the improvements made to the item. Obviously, it's very unlikely that many people will go through this whole process, and even if you did get Form 4455 signed in-person in advance, there's no guarantee that the people shipping the item back for you would do everything correctly. That's why I've never bothered to do it, it's just too hard and not worth it.
As Al mentioned, sometimes CBP will waive these requirements if the item is returned and marked as for repair only. CBP makes a lot of discretionary decisions. However, the process below is what you are officially supposed to do.
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Duty on goods purchased overseas being exported for repair, alteration, etc.
Repairs or alterations means restoration, addition, renovation, re-dyeing, cleaning, re-sterilizing, or other treatment which does not destroy the essential characteristics of, or create a new or commercially different good from, the good exported from the United States.
When exporting goods purchased overseas for repair, alteration, processing, replacement, exchange, upgrade, or for use abroad, it is recommended that the exporter fill out a
CBP Form 4455 Certificate of Registration and include a copy with the shipment. Prior to shipping the goods the exporter must bring the items and the form to a Customs and Border Protection (CBP) location and have an Officer physically inspect the goods being exported and sign off on the certificate.
When sending goods overseas, the exporter should send the overseas supplier a copy of the CBP Form 4455 in the package and have them return it with the goods when sending them back to the United States. This will let the foreign country customs and CBP know the purpose of the import into either of their countries. The form should be in the package and easily accessible, so when the item is returned to the United States and examined by CBP it will be clear to the CBP Officer that the goods were previously in the United States.
Also, ask the overseas supplier to include in the return shipment an invoice with any cost incurred for repairs, alterations, processing or differences in the cost for the replacement, exchange, or upgrade if any. The cost of repairs, alterations and processing may be dutiable, depending on the commodity and origin of the goods.
If repairs were made under warranty, please have the overseas supplier indicate it on the invoice. If the goods were replaced, exchanged or upgraded and the value of the goods is more than the original purchase, have them indicate on the invoice the price paid for the new item and the difference between the cost of the new and original purchase. Duty may be required if the difference is a substantial amount.
Goods that are being returned to the United States after being used abroad, such as for exhibit, tools of trade, etc. are not subject to duty as long as the condition of the goods did not improve and the value did not advance.
Articles exported from and returned to the United States after having been advanced in value or improved in condition by repairs or alterations may qualify for duty exemption under the Harmonized Tariff Schedule (HTSUS). See
19 CFR .
An
ATA Carnet might be another option for traveling with this category of goods.
Chapter 98 of the Harmonized Tariff Schedule contains the rules that cover these importations.
