The document discusses how to determine an appropriate marketing budget based on key business metrics. It recommends starting by calculating the lifetime value of the average customer based on annual sales, gross margin, retention rate, and present value. The business rhythm, closing rate, and source of leads should also be considered. Marketing spend should be 30% of the average customer lifetime value. An example is provided where the average customer is worth $1,295, allowing for a $3,880 marketing budget aimed at generating 10 new customers. Spending should be measured based on relevant metrics like traffic, downloads, calls, proposals, and sales. Increasing referrals can help reduce marketing costs.