When viewing a property here are the things that I recommend to always take, a camera / mobile phone, tape measure, ladder, and binoculars.
It is always a good idea to take photographs on a viewing, so taking a camera is a necessity.
A tape measure will enable you to check room sizes etc within the property.
You may be able to view the loft on a viewing, so a portable ladder will be useful.
Binoculars will enable you to take a look at the roof and other areas that are hard to access