The answer depends, in part, on the platform you are using. For example, hashtags are not "clickable" on LinkedIn so there's little point. The question to ask yourself is, I think, whether a hashtag adds any value for your reader. If it doesn't, skip it. I often see posts on various platforms with a bajillion (ok, not a technical term of any kind) hashtags and @ symbols. When that starts to interfere with understanding and communication that irks me. If the point is to communicate an idea to your reader I think you are better off honing the idea than searching high and low for hashtags in the hope that people will think you are somehow more "in the know" than the next person. Communication should be about substance not form and in many cases the hastag is nothing more than a fancy corsage. BAM don't strike me dead Twitter.
One of the most comprehensive posts on hashtag use and recommendations is this one by Buffer’s blogger extraordinaire Kevan Lee. Lee breaks down all the key, data-backed recommendations for hashtag use across all the major networks, including Facebook.