If you are a small business or just starting out, you want to make sure you are getting the maximum benefit for each dollar you invest.
Then you want to take advantage of compound interest.
Everyone on the Internet at one point is searching for something online. Those searches can vary between showing a minor interest in a subject to being highly motivated to buy. You want to have resources for those who are looking but you want to have highly refined content for those who are interesting in buying. There are a number of ways that you can determine how motivated a searcher is and how to direct them to the right resource page for their search. You need to make sure you select the proper keywords in your online ads to capture the highly motivated buyer and then seamlessly move them through the buying process.
THis is where you take advantage of compound interest, you want to segment your revenue to reinvest into your ad campaign to drive more business. The rule is if you know you can invest one dollar into your buyer system, the more dollars you put in the more business you can close. The only consideration after that point is to make sure you can scale correctly. You are constantly testing your last successful campaign to see how you can improve it. The more minor improvements you can make, the more it compounds in revenue dollars for your business.