When Plan Mode Pays Off vs. When It's Just Overhead

For each of the following four tasks, decide whether plan mode is worth the round trip or is overkill, and justify the decision using at least two of the signals from this subject (scope clarity, blast radius, familiarity, reversibility, task size):

A. "Rename the getUserById function to fetchUserById across the codebase; it's called in 4 places, all in files you touched last week."

B. "Add rate limiting to our public API — figure out where it should live and what limits make sense."

C. "Fix the off-by-one error in paginate() — line 42, should be <= not <."

D. "We're deprecating the v1 internal auth token format. Migrate every service that still issues or verifies v1 tokens to v2."

Then explain why applying plan mode uniformly to all four — "always plan first" — would be a worse policy than deciding per task.