I am happy to say "ALMOST" never.
When you buy from top dealers in the hobby to can be 100% assured that you will receive a perfect piece. I do a lot of dealing with
George at Minuteman and
Nicholas at Crown Toy Soldiers,
Matt at Hobby Bunker and
KingsX; Never had an issue. But I know if I did, it would be fixed immediately.
A lot of that is due to their attention to detail and service.
Also, the packaging on K&C (at least the recent boxes) and John Jenkins is wonderful.
Still, I have ventured into the eBay world and once in a while I have been a bit disappointed when I see the figure up close. Only once in 15 years have I been burned.
(But Also, a set of Tamiya, or Model Master Paints and an OOO brush can work wonders!!!)
Larry