Other Vivas
Every viva is unique. Every viva is similar and different to every other viva. Vivas follow patterns. Vivas are not mysterious but you don’t know what will happen until you get there. Expectations are not guarantees.
Hearing about someone else’s experience at the viva can help you to understand what yours might be like. Learning about what happens generally can help put some parameters on what you can reasonably expect for your own.
But finding out that a friend didn’t enjoy their viva doesn’t mean that you won’t enjoy yours. Discovering that a group of friends all had long vivas might set some expectations with you, but doesn’t provide guarantees.
Finding out about other vivas is useful but only part of the process of getting ready. Read the regulations, ask your friends and colleagues about what happened and then use that information to help you as you prepare.
Your viva will be the same as many others and also different from every other viva. You can still be ready to meet your examiners and succeed on the day.