[REF] User testing is common sense.

When you should do it

User testing can be carried out at any stage of a design, from the initial concepts to the final product. In general, the most efficient way of carrying out user testing is to do it as early as possible in the design process, so that fundamental problems are eradicated before further design work is carried out. Then test often. Some feedback secured at the beginning of the project is great but it’s not enough. Keep validating your assumptions – even if it involves just showing it to 1-2 users.  The best approach to testing is to start early and test often, using an iterative development process of design, test, update, test – etc