The other day I needed to use it for the first time in a year. A package that is used in many other packages host by npm was returning a 404. Slowly stackoverflow started to fill up with similiar questions.
Apppearly 4 important packages were unavailable in my region because they were deleted by accident. Some people were vpning into Europe, I found an Italian mirror.
Not sure if things are always that crazy but I don't have a reliable feel.