Hi Lilbobeep, my first viva was cancelled as my thesis was 'so unsatisfactory'. After three years I went back to it. Started re-writting on the 21 April and send it, completely re-written (with about three paragraphs not re-written) to my sup on the 22 July. it went back and forth a few times but it was submitted in the October. So a short answer is 12 weeks (and I was working FT). But as Chuff says chunk it down, I had a massive list, with timings so however much time (from 10 mins to 10 hours) I had I knew there was something to do. It is so worth it in the end, and one really good thing is you know exactly what your examiners want (because of the major re-write, including changing my philosophical slant, my examiners changed so I had no idea as I entered the viva what would happen, it could have been another re-write). Go for it, and keep us posted!