I try to avoid it at all costs, except maybe Canada. It usually costs more, takes longer to get there (more time for it to get lost), customs paperwork can be a pain (don't mention Ivory G10!!!) and I had a knife go MIA going to France many years ago and I had to replace it on my own dime. Some customers want the paperwork changed so they pay less taxes/tariffs/duties, etc, which can get the sender into hot water, especially if there is a insurance claim for damage/loss. More of a headache than it's worth for me honestly!
Some serious buyers have someone or a service in the US that they have items shipped to, and then either forwarded to them, or they pick them up when they visit the US.