When should I use both flags?

You should use both the -i and -t flags (-it) when you want to run a container interactively with a terminal interface. This is particularly useful in the following scenarios:

Running a Shell: When you want to start a shell session (like /bin/bash or /bin/sh) inside the container, allowing you to execute commands interactively.
```
docker run -it ubuntu /bin/bash
```
Debugging: When you need to troubleshoot or debug an application running inside the container, having a terminal interface makes it easier to run commands and see output in real-time.
Interacting with Applications: If your application requires user input or interaction, using -it allows you to provide that input directly.
Development: During development, you might want to test commands or scripts interactively within the container.

In summary, use -it when you need an interactive terminal session with the container for better usability and control.