If your conditions and limitations are ones that would be better explained with a diary then you should think about including one, for example; if your problems vary over time or even just within a day. It can also help you to document your issues in a broader form than you might manage on the form.
You really need to do as long a period as you can, either to show any variations or to indeed to show the consistency of your problems.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems