In general, this depends on the labelling standards. If you are using GS1, see their standards for UDI labelling
GS1 Healthcare GTIN Allocation Rules Standard | GS1 . I am not familiar with HIBBC standards.
Need for new UDIs is determined by those - for example, if you, per GS1, label the same product with two languages (different labels for same device), you need two UDIs, if you combine them you need one. If you add an additional trade name, you need new UDI, etc.
There may be specific national requirements for the product driving a need for new UDI, as described above (different language, different user profile, different materials, diferent indications...).
This info is based on my current knowledge.