Tashabella
Don't change your routine just because of the assessment, if you would normally get up and get dressed at that time of day then do so but if you wouldn't then don't just because the assessor is coming.
They will view you as they see you without asking questions about whether this is what you would normally do.
The PIP Claim guide has sections on the assessment and the questions you are likely to be asked.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems