Vision does not have to be in writing, or may be defined and implemented short length doesn't matter, but what is important is the use of vision for all employees in an organization must understand that its set up.
Vision need not be in writing. Or may be used to define the short term it does not matter. But the key is the vision that every employee in the organization must understand what the Organization established organizations.
Vision, no need to be written. Or maybe set used short how long is fine. But more important is that vision use all employees in the organization to understand what corporate set .