Again, For The Final Time
That’s the viva. You’re doing something you have done many, many times throughout the last few years – thinking about and talking about your research and your ability as a researcher – and this is the last time you’ll need to do that.
(you might want to do it again, you might want to be a researcher or have a career that involves this – but you won’t need to do it after your viva)
At your viva you need to discuss your research contribution, your PhD journey and what you can do as a researcher. These are all things you must necessarily have done a lot during your PhD. The viva is a particular challenge which requires particular prep, but it’s not so different from the rest of your PhD experience.
The viva means doing it one more time. Maybe the last time.