Use of the 'Recurrence Frequency = Never' setting for Billing Schedules

This is set when user wants to do one time billing only. In this case, it is recommended that user set Billing Schedules=Mandatory in the transaction form so the correct Billing Schedule will be selected in the transaction (provided that the Billing Schedule is not set in the item record). User may alternately set this Billing Schedule in the line item should he opted to do one time billing only.    

Note: This is only during rare instances, the mere fact that Billing Schedules' main purpose is for recurring billing.

This can be found via : Lists > Accounting > Billing Schedules > New > Recurrence Frequency = Never