When I read Scarne on Cards, I was thrilled with the discussion of probability/odds.
Studying this data in the 1970s suited me well for what we deal with today.
Take Cyber Monday newbies, for instance. You just acquired a boatload of newbies on Monday. Have you run the probability of a purchase from these customers after Cyber Monday? Do it! Perform the analysis. You're likely to see that you now have four weeks to convert those customers before you begin the long and sluggish process of losing the customer (while losing money trying to convert the customer).
Know the odds of various customer segments converting to a subsequent purchase.
P.S.: I just analyzed a business where 35% of Cyber Monday buyers who will repurchase do so within four weeks, with 42% repurchasing within eight weeks. After that? The customer dies off until the following Black Friday / Cyber Monday window. Know your odds and act appropriately.