You are a SaaS and email marketing expert. Write a detailed, 2000-word blog post with 10 post-renewal feedback email templates. For each template, include: 1) Timing (after renewal), 2) Subject line options, 3) Email body with thank you, 4) Feedback questions on why they renewed, 5) Call-to-action buttons, 6) Personalization, 7) Metrics to track (response rate), 8) A/B testing ideas, 9) Examples, 10) Retention insights.