A perfect score would be 555. RFM (recency, frequency, monetary) analysis is used to determine who are your best customers by examining how recently a customer has purchased, how frequently they purchase, and how much they purchase. RFM analysis is based on the pareto pricipal that 80% of your business comes from 20% of your customers. You can then use these numbers to either re target them and find look alike, while not wasting time on those with low scores.