Developer workflow: Does it matter which port is used during development?

Are there any differences between choosing this or that port? Are there any standards for picking a port?

I'm just looking for the "why" a particular port was picked to be used. There doesn't appear to be a standard convention for picking a port number(at least in documentation).

The examples in official docs use different port numbers.

• Create React App docs provide examples using localhost:3000/
• Django docs provide examples using port 8000/
• Ember docs provide examples using port 4200/
• Express docs provide examples using port 3000/
• Flask docs provide examples using port 5000/
• Webpack docs provide examples using port 8080/