Most companies work exclusively in one mode or the other.
If you are one of the many companies that still work exclusively in the inch mode, you probably don't know about the accuracy advantage of the metric mode. This advantage has to do with the least input increment of the input mode. The least input increment in the inch mode for the vast majority of CNC machines is 0.0001 in. In the metric mode, the least input increment for these machines is 0.001 mm. To get an understanding of this implication, consider a common indexer.