Here's a mid-thought observation that will optimize retention by key version: data encrypted with old key versions (superseded, potentially compromised) should be retained shorter than data with current keys. Your 

A short relatable scenario that will personalize win-back based on fog: on heavy fog days, outdoor activities are limited (driving hazardous, views obscured), so people stay inside and watch more TV. Without fog-based personalization, you miss the fog-

Here's a confident contrarian opinion: customers want to know when their account is accessed from a new device or location—it makes them feel secure and gives them a chance to respond to unauthorized access quickly—but most