The following is from the April 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: I purchased your book and have a few questions you can hopefully help me out with. A: Thanks for that, and sure! Q: We have 4 product lines and 2 of them are seasonal. i.e we have customers that year in year out purchase......