My wife found beautiful curtains in a local charity shop. They were a lovely pattern, they would look good alongside the colour of our living room walls and tone in with the furniture. They were clean and in great condition, and the shop was asking a very fair price for them.
She brought them home, and I leapt into action. Stepladders out, old curtains down, curtain hooks off, hooks on the new curtains and back up the stepladders to hang them.
And discover that the beautiful curtains were six inches too short for the length of our windows.
All of which is a fun little true story to say: find out as much as you can about realistic and relevant viva expectations before you take steps to get ready for your viva. Make sure that your understanding of the viva measures up to expectations – rather than have your actions fall short of what’s needed!