Why do manager need to plan?

Why do manager need to plan?
It is important for a business to have a plan. And it is the manager (or owner/shareholders) job to make sure that plan is sound. The plan is split into objectives, and aim.The aim of the business is their overall goal, for example to become to largest provider of DAB radios in EuropeTheir objectives are smaller, for example, to set up a store in the united kingdom by 2010.Why is it important for the business to have a plan? Well, for one it gives the business something to aim for, to keep their workers motivated, and to keep them on track. It also gives the business something to see how well it has been doing, and where it needs to improve.