Complex sentence: For the majority of businesses which will add value to a product or service which will be purchased by a customer, advertising is often a component of their business plan and expenditure for this particular component is forecasted as it can generate greater revenues over periods of time.
Split into simpler sentences: For the majority of businesses which will add value to a product or service that will be purchased by a customer, advertising is often a component of their business plan. Expenditure for this particular component is forecasted as it can generate greater revenues over periods of time.