Marketing employees can certainly help you improve your SEO, but the main reason for outsourcing your SEO is because it will be easier. It's also way cheaper. A seasoned marketer makes an average annual salary between 50,000 and 60,000 dollars plus you'll have to provide them with a computer and other equipment, pay for their benefits, vacations, and sick days, etc. An SEO agency typically costs between $1,800 and $5,000 each month (on average). They don't require any training in the field, they don't need vacations, they don't require any special equipment and they guarantee their results.