Second, find out how frequently your clients use your service.  How much do they buy?  When?  This is particularly vital issue for service providers to understand.  Often there are opportunities to increase client patronage that you are not aware of now.

- Jean Withers and Carol Vipperman, Marketing Your Service

Last week, we considered the value in looking at customer groups - traits our customers have in common.  This week, we're building on this by considering when and what they purchase.  Revisit the list you made during last week's tip and add information that answers the above questions.  How often do your various customers purchase from you?  When do they do so?  Are they small or large purchases?  Look for trends in your answers, then consider: is there something you need to change in the way you market yourself to capitalize on these trends?