[kevan]

The key to sleeping at night is to add metrics and alarms near those cliffs or 'edges of the map' so they aren't invisible anymore. It's hard to anticipate every angle to this but in any case where you're making this kind of assumption or tradeoff it's a good idea.

A simple example is setting an alarm on your max load test traffic. When you get that alarm you know your system is now operating in unknown territory and it's probably time to do another load test or at least take a close look at scaling.