Two versions of this keep coming up and I don't think they're one question. A jar that arrives by post, or one you bought abroad and carried home in your suitcase.

Nearly every answer treats them as one problem, does country X allow it or not. But if shipments and travellers' goods sit in separate channels with their own paperwork, a personal import isn't a softer commercial one, it's a different category. Or I'm inventing structure.