The following is from the February 2011 Drilling Down Newsletter. Got a question about Customer Measurement, Management, Valuation, Retention, Loyalty, Defection? Just ask your question. Also, feel free to leave a comment and I’ll reply. Want to see the answers to previous questions? Here’s the blog archive; the pre-blog newsletter archives are here. Q: Thank you for creating this useful website! A: You’re welcome! Q: When figuring out retention rate for an annual or a 8 months life time cycle period, how do I pick the starting period? Do I look at their first orders on a date? ......