How often should you post on LinkedIn? Well, it depends on your purpose or strategy. I know a Doctor that posts daily tips and let me tell you, she is ALWAYS in the front of my mind. I just referred someone to her recently too. Do you HAVE to post daily? No, but it can't hurt.
I'm sure you've noticed that LinkedIn posts are delayed a bit so you'll see current posts and posts from a couple days ago... probably depends on the last time you actually visited your account.
Anyway, LinkedIn is a great platform for reaching out to your target market in a professional setting... think of LinkedIn as the boardroom of social media. A little bit more serious tone to this platform and posts need to be strategically created this way.
ps. As always, if you need someone to strategize, reach out!