For the most part unless your part of the entertainment industry or a politician you don’t need a huge or even daily presence on Social Media. Even then your not necessarily going to need to be on Twitter. Instagram is for your customers to use to show others how great you are.
That being said you should use Facebook if nothing else but to show people your hours, website, etc.. The others it’s good to have some sort of what is called a Hashtag or the # pound symbol for your business. This is pretty easy to set up, just make one. You might want to look around and see what others are using what you choose but find a unique one. Putting up a sign that shows your Hashtag makes it easy for those that will do it.
Contrary to popular belief the presence on Facebook isn’t a part of Google and how it determines if you even exist. That is handled more and more by Google and how it figures things out via all the data people are feeding it on a daily basis.
So deciding on your social media presence really depends on your type of business, but for the most part it’s a waste of time and energy. You could spend that time working on things that will really improve your ranking with Google Search.