Hi Karen
I'm sorry - but you've left it a bit late to ask that question. The guide to PIP claims and reviews tells you the sorts of questions that you may be asked. It is not an exhaustive list and they can always throw in a question that you're not expecting. Pages 123 - 126
benefitsandwork.co.uk/guides-for-claimants/pip The length can vary - but the average is about 1hr 30 mins.
Don't forget to record the assessment if you're able to.
Have a glass of water ready and pen and paper if you need to take notes.
The best of luck.
BIS