Predictability can be good or boring.
I want to point you to the positive side of being predictable as it relates to online marketing.
When it comes to Facebook marketing, you can establish predictability for your followers by finding out when your followers are online and schedule your posts for the times most of your followers are active.
You want to build relationships with those who may benefit from your service.
Posting on Facebook and social media allows people to watch you and get to know you better.
People buy from people they trust.
To establish your presence online allows for building trust and trust is the first way-point on the client's path to you.
Let the people know you, be transparent but be professional. Always remember why you post and what you want to achieve with your posts.