Vivas vary because every thesis and every candidate are different. Regulations create a layer of structure. Good practice for vivas creates expectations. You can’t have a script but you can reasonably expect a viva to have certain standard features.
- You can and should expect examiners to prepare.
- You can ask for a break at any point.
- Vivas tend to start with a simple question.
- Corrections are a standard request for candidates.
Success is part of the standard viva. More than anything, it’s expected you will pass.