Change windows fit people, not servers
A change that races to zero traffic but lands when nobody is watching trades one risk for another. The best window is one where the operators responsible can actually attend. Traffic is only part of the math Deploying at the absolute quietest hour minimizes how many users feel the change, but it collides with the people problem: the operator is most likely asleep, unreachable, or already covering another incident. If the rollout breaks at 3 a.m. and nobody is watching, a silent failure can run for hours before a human reads it. Least-traffic is a good starting estimate, but it is a traffic answer, not a risk answer. Balance reduced exposure against the ability to react, and prefer a window where you can actually observe the result. ...