A few times per day is ideal for optimal customer engagement. Especially on time-sensitive social media feeds like Twitter and Facebook, people are going to see the fresh stuff, so you want to be sure that a wider net of social media users get to see that content.
My team has developed a social media calendar with a formula that we’ve found works for us. We use a combination photos, videos, polls, news updates, a funny quote, a customer feature, anything to change it up and keep the customer interested. By varying it a lot, you’ll eventually find out what speaks to your audience base the best. At the end of the day, this ideal formula is going to change according to your specific audience. Test it out and analyze the data.