Again outsourcing your SEO totally depends upon you. If you are a proficient SEO strategist with years of experience and are familiar with the ever-changing SEO tactics then you can do SEO on your own. But if you are just starting out then learning SEO and then implementing them on your own will take a lot of time. You might argue with the statement that your company has an in-house team but as SEO policies are very volatile and are constantly updated you might seriously consider outsourcing SEO services. SEO is the main specialization of such agencies so they put their blood and sweat to increase your rankings through their strategies. They are also updated with the recent developments as SEO is their bread and butter.