John Paul Sartre would have had a heyday living in the social media age. Which is more real, your physical existence or your digital existence? Who knows, and I'm not here to debate it either. The existentialist introduction was simply to set the atmosphere for the almost mystical question that I am here to address. It falls somewhere between the completely abstract "why is a duck?" and the considerably less bizarre "to post, or not to post?" It is asked repeatedly, and it receives a wide range of answers, all sincere, most ridiculous.
That question is: "How often should I be posting to Facebook, Twitter, LinkedIn and others?"
The answer is obvious of course. Facebook posts should be sent exactly 9 times each day, with nor more than 3 clumped within a 2 hour period. On Wednesdays you should add 2 posts at midday and on Thursday evenings you should skip one. Twitter is 14 times each day between 8:34am and 3:27am, with no more than 3 repeated. Pinterest should be avoided between 5 and 7pm weekdays but can be doubled up on Sunday afternoons, particularly during football season. LinkedIn is more of a weekday 9-5 things since it's business oriented, and you don't want to repeat things very often there either. As for Google Plus, since it's mostly males interested in tech... hey, you still with me?
If so, why? That insane answer came from the top of my head, but if it had been derived from years of data it would only have slightly more credence as an answer. Your business is unique, your employees are unique, your customers and clients are unique. Why wouldn't the solutions for your business be unique?
Consider your customer base. Say you had 4 mothers of 3 children each in your base who were all 29 years old, and each mom had 2 girls and 1 boy, but they lived in Montana, New York City, Miami, and Seattle respectively. With so many similarities, they would still probably vary immensely on most of their habits and hobbies. Using statistical data is a very generic metric until the data comes directly from your customers. Then it means everything.
I'm using blanket statements just to push the point a little, but obviously there is some validity to statistical data or they wouldn't still teach statistics in school. My point is that this data should be a piece of your decision-making process, and that the bulk of that process should be based on your own specific data. That is the most effective formula for sharpening a marketing strategy for better penetration.
So please don't turn your back on statistics forever on my account. They are perhaps the best shortcuts for jump-starting your planning, because they give you a generic baseline from which to start measuring. Once you start your own measurements, however, the truly important data will begin to roll in and give you a preliminary answer to your question.
How then do you establish your own metrics and data collection habits so that you can schedule your posts to optimize their engagement? Very simply by using software, specifically a quality social media dashboard. The dashboard will allow you to create and curate posts (using the 80/20 rule) and then schedule them using whatever statistical data you want to, such as this infographic of the best times to post to different networks produced by Fannit.com.
Once you have sent out several weeks or more of scheduled posts, you can use the analytics and reports to create your own baseline to move to. Better dashboards will not only automatically determine the best days and times based on your real engagement, but will also provide you detailed reports and customizable reports so you can derive your data the way that suits your company best. They will also allow you to customize or "white label" your posts so that they don't appear to be coming from third-party software, creating a more professional appearance and increasing even more the probability of engagement.
If you're still hoping for some quick-fix answer to take away and implement, I'll at least give you a formula that will definitely work.
Your customers' social habits + entertaining and engaging content + data analysis of reactions to your posts over time + a good social dashboard = Optimized posting and more sales
That's the best I can do, but it's also the best anyone else can do. Don't buy the snake oil being peddled about what is best for your customers and your business. Your own research will be immensely more valuable. All you need is the right tool, and a comprehensive piece of social media management software will do the trick.