When should you create your own namespaces?

Question

C++ / C#

In what situations in C++ code should you create your own namespaces?

Answer 1

In my opinion, this should be done in almost any program, because. this will protect against duplication of function names, and it's easier to navigate through pieces of code this way, and it's a convenient method to split code into modules.

Answer 2

When a system of classes, constants, functions, possibly global variables and objects arises, which describes the essence of one task or a set of related tasks and creates tools for solving them, for any actions with these entities.
For example, a namespace containing classes for describing sockets, IP addresses, connections, functions for creating a connection, accepting an incoming request, sending and receiving data. Or another example: a set of different algorithms for working with matrices, defining the type "matrix" and "vector" as standard or user-defined using / typedef.