Almost every country in the world uses metric measurements. Every country except for the United States that is. It’s usually not a big problem. But there have been some close calls throughout history when people used metric instead of imperial, or vice versa with disastrous results.
I stumbled across this YouTube channel this week, specifically regarding the use of commercial-quality networking equipment in you home. The approach in this video is exactly what I would recommend for anyone to properly set up their home network. It’s very similar to what I run at home.