My favourite teacher in high school, Mr S., used to have a set of “laws” on his wall. First among them was a lazy mathematician is a good one. He would repeat and explain it a lot, because he didn’t mean we shouldn’t do any work!
His point was that a good mathematician knew lots of methods so they would know how to solve a problem with the least effort. A lazy mathematician would find only the answer they were looking for, and not waste time on other details. A lazy mathematician would think first and recognise what they needed to do before starting to solve an equation or draw a graph. Consequently, a lazy mathematician might seem to start slow, but would probably finish quickly.
For similar reasons I think that viva prep needs to be “lazy” too.
When getting ready for your viva, don’t do what you don’t need to do. Stop and consider the outcome you’re working towards before you get going. Reflect on your skillset and knowledge before committing to a hectic schedule of reading, writing and thinking. What tasks and practices do you really need to do?
You need to be ready for your viva, not ready for anything.