Taking a break before evaluating the writing helps with many things. It gives new lenses of changes that need to be made, it reduces fatigue, and allows a new set of ideas to be come up with. By taking a break, the writer is able to freshen his or her mindset and be more critical in assessing their writing. It becomes easier to identify errors or inconsistencies as well.
Before evaluating writing, it is always important to relieve yourself mentally of the situation. This allows you and others to come in with a fresh mind and more effectively critique the work.