We found the golden balance between frequency and quality of posts. If you provide valuable knowledge for your audience while not spamming features about your product, you won’t be annoying anyone. At least that’s what worked for us in the past.
About once a week, I know I should do it more often, but Blocks' page is too small now, so can't overcome the barrier of just wasting time on the social media almost no one is following now (know it's a vicious circle though)
I try to do a variety of content so that I am not always promoting! I think it’s important to give people a variety so that they are not tired of just one thing! Also helps you capture a wider variety of audience.
As already mentioned be previous poster, we tend to post quality and laser focused posts that reverberate to the target audience.
Naturally interaction with the audience is also required, which at some points requires additional posting to support/assist/prove a point.