<p>I'd divide up the territory, without claiming a complete analysis.</p>
<ol>
<li><p>An answer you now see as <strong>wrong</strong> should be deleted.</p>
</li>
<li><p>An answer you now think is <strong>irrelevant</strong> possibly should be deleted. Irrelevance need not be a matter of blame: often it becomes clear that the original question was not really what most concerns the OP. But sometimes your interpretation of the question remains a possible interpretation for someone else. The OP owns the thread by being the only person who can &quot;accept&quot; an answer, but the OP lacks exclusive rights otherwise.</p>
</li>
<li><p>An answer you now think is <strong>partial</strong> possibly should be deleted. Sometimes people fill in silence with what they know is incomplete but may still be helpful or interesting. But then better answers may appear. How far such an answer should have been a comment can be a delicate decision. For example, I will sometimes post a partial answer if I have comments and a graph.</p>
</li>
<li><p>An answer you now think is <strong>redundant</strong> — because later answers are clearer, more comprehensive, or just better while not contradicting your own — possibly should be deleted. But answers can be complementary, a short and sweet answer being useful as well as a lengthier, fuller analysis.</p>
</li>
</ol>
<p>The overall advice is easy — delete if you think that will improve the thread! But as you say deletion doesn't just remove (NB) an answer, it will remove (NB) any associated comments. In statistics it can be true that comments are about as valuable as answers, so thinking about the damage in removing comments is important too. (NB: &quot;remove&quot; is a simplification here, given that much material remains visible after deletion, depending on your reputation.)</p>
