The main aim of this point is to get across that you should not jump straight into the job and start laying the flooring straight away. Take the time to plan out the job exactly.
While it may work for some to just start laying the flooring straight away it can cause major cosmetic problems. As you move from room to room angles can change as rooms are never perfectly square this leads to crooked flooring spreading through the rooms, a slight change in angle from the required 90 can have major consequences leading trouble for the fitters having to trim down flooring and as mentioned earlier the cosmetics of the flooring will be harmed.