This article assays linguistic factors affecting the author’s selection of discourse connectives in written texts. It centers on the competition of primary connectives (e.g. therefore) and secondary connectives (e.g. for this reason). It proposes a corpus analysis of connectives in the Prague Discourse Treebank 2.0. Sorts of constraints on connective selection are: syntactic, semantic, pragmatic, stylistic, and long distance (salience). Factors affecting connective use are: grammar; the principle of least effort; the effort to shun misconceptions.