According to Buffer their best practices for posting frequency will probably surprise you, it certainly surprised me. If you are a smaller business and only using 1-3 channels, then it should be less daunting unless you have someone looking after these accounts for you to take care of content.
Facebook 1-2 times per day (8-15 per week)
Instagram 1-2 times per day (5-10 per week)
Twitter 3-10 times per day (21-70 per week)
Linkedin 1-2 times per day (8-15 per week)
Pinterest 5-10 times per day (35-70 per week)
Instagram Stories 2x times (8-16)min per week
Snapchat 2x times (5-10) min per week
The above stats in my opinion are focused more on larger businesses, as they have the resources to post so much content, though as a small to medium size business, why not try focusing on the most effective channels for you with consumer interaction. The Facebook and Instagram figures are achievable, though why not also try at the lower end recommended twitter posts per day (3).