SEO. Social media page valuations. Ad revenues. Search analytics. Organic Growth. CPM converion.
These are critical aspects of building a brand in that you are able to measure and promote your core product. But how much of an emphasis should be placed on these vs your core product?
Focusing on Core Business
Unless the marketing tools listed above are your areas of expertise/majority revenue source, your goal should be to minimize the amount of time spent managing social media marketing. Companies that can help you manage this range from niche boutique firms to full-fledged enterprises that can handle end-to-end marketing budgets.
Too often we feel like we have to have the media presence of Grant "The King of Random" Thompson or 
Your key to success for having this managed externally is all about defining the scope, amount you are willing to spend, and expected outcomes. If you fail to do this, your marketing strategy will fail.
Active vs Passive Management
Of the many named strategies, there are really two strategies to adopt: 1) the "RonCo-Rotisserie-Set-It-and-Forget-It" strategy, or 2) the "Actively-Manage-Scope-and-Performance" strategy.
The "RonCo-Rotisserie-Set-It-and-Forget-It" strategy will yield the same results every time. Every. Time. Whenever you want to expand/grow, you will be subject to the sandbox that you are told you can play in. You may be able to make small adjustments, but you will be assuming that your marketing knowledge will be able to take you to the next level. The value proposition being communicated is consistency, not efficiency. This strategy effectively gives you a megaphone in a world with many, many megaphones.
When you make the decision to actively manage your social media service provider, you are able to track performance vs. expected outcomes. You are able to adjust your expenditure and target the areas that are paying off the most. The scope of your social media strategy will be understood, but will not take away for your core business. Instead of a broadcasting on a megaphone, your active management strategy gives you the power to authoritatively invite relevant parties to enjoy the value you can bring to them.
Results
You as a business, brand and/or individual are focused on results. Those results translate to either opportunity, money, or some combination of the two. And while money will never bring happiness, it provides economic freedom to focus on those things that provide you happiness.
Being focused on the results of the social media branding you are doing/paying for will bring you closer to your goals, and give you more time to master your trade.
