You might need slides for your viva if your examiners ask you to prepare a presentation. It’s not a common experience, but it does happen.
If you need a presentation then prepare carefully: think about what your examiners need to know, what they might need to see and how you can best summarise what you have to get across to them. Your supervisors and possibly your friends and colleagues can be valuable in helping you to know what you have to include and what you have to do.
If you need a presentation then you would have to practise. Don’t simply copy and paste old slides together and rely on old memories. Rehearse your presentation if you’re asked to prepare one for your viva.
And if you’re not asked then you don’t need one! Simple as that.
Although, if you’re not asked for a presentation for your viva, putting together a slide deck could still be a helpful way to bring your thoughts together.
A few bullet points on each topic. A few images that help you remember. A logical sequence of information to organise your thinking. Something simple to scroll through and refresh your memory on the days leading up to your viva.
If you’re not asked for a presentation then you don’t need one – but you might still get help from making a slide deck. Simple as that.