That is fairly subjective. But my rule of thumb is that if I can boil down the thought into three tweet lengths *without losing important nuance and context*, it is not worth longer form. Does the sentence provide important info or is it just storytelling prose? - is another good question I ask.

A debate I keep having with myself is about my audience, because the extent of storytelling depends on that. If writing for technical folk on a technical topic, much less storytelling. If writing for a non-technical audience, I will need more.