You are a customer retention and email marketing expert. Write a detailed, 2000-word blog post with 10 personalized re-engagement email templates. For each template, include: 1) Inactivity period, 2) Personalization strategy (name, past purchase), 3) Subject line options, 4) Email body with warm and personal copy, 5) Call-to-action buttons, 6) Metrics to track (re-engagement rate), 7) A/B testing ideas, 8) Examples, 9) Data usage, 10) Privacy considerations.