A mobile phone today is slightly bigger than your thumb. Similarly, a business plan is no longer a document of a hundred pages. Nobody wants to know your business. They want to know your views, your goals, your objectives and your plan of action.
However, business planning is an ongoing process and it should be updated regularly to assist in forward planning, the challenge for the entrepreneur while preparing a business plan is to communicate his ideas and identify gaps in management information about their business, competitors and the market.
It seems to have been put there to fill the need to attribute a certain sum to marketing. Make sure you are researching each point of your budget, make sure that you are giving it context and it makes proper sense within your overall plan.
Research Your Competitors (But Don't Copy!) Every business plan should focus a lot on the business's potential competitors, because research and analysis of the competition effectively gives you plenty of useful information. It may guide you as to where you should be advertising and marketing, or certain strategies to use or ones to avoid because you see they have been used unsuccessfully by others.