Example here to use:
We have a customer that makes multiple small purchases, we invoice for each purchase but he doesn't pay until all of the invoices amount to £50. Similar to a monthly statement, except that £50 could be reached in a week or 7 months so it is easy to lose track of him (with all the other things you have to concentrate on!)
I think setting up a credit limit on the customer account would resolve this problem for me and any others that may have issues with slightly unreliable payers on the monthly statements. This could be not letting new entries be entered once the limit has been reached, or flagging up a warning, or emailing that the limit has nearly been reached etc.