Most industrial products are manufactured in set sizes or modules. Some building components such as concrete blocks are manufactured to 200mm modules.  Walls built from concrete blocks should be designed to modules of 100mm and preferably 200mm modules otherwise, it will be necessary to cut the concrete blocks on every  course.  Similarly the height of concrete blocks walls should be in modules of 200mm with due allowance for rebates etc. Many sheet materials are manufactured to a width of 1200mm and lengths of 2400mm, 2700mm, 3000mm and so forth.  While cutting of sheet materials is often unavoidable, the underlying framing system should be spaced 400mm or 600mm in one direction and 300mm, 600mm or 800mm in the other direction.