The numbers being printed in the same position on every card, all tabs placed over the same number will be in a direct line in the file. The cards to be removed for the follow-up on a certain date are those bearing tabs over the number representing that date. On June 20, for illustration, all cards with tabs over No. 20 are taken from the file. When letters have been written, the tabs are moved to the next follow-up date, and the cards returned to the file. [Illustration: Fig. 27. Card for Combined Daily and Monthly Follow-up] This method of cross-indexing with movable tabs permits of the filing of the cards in any manner desired, with the knowledge that the follow-up date will be surely indicated. The tab method is also used for a combination of daily and monthly index. On the card shown in Fig. 27, the names of the month are printed under the date. For a follow-up in a later month a colored tab is used to represent the monthly index, while a black tab represents the day of the month. To illustrate, we will suppose that the card is placed in the file on Oct. 5 and the next follow-up date is Nov. 10; a black tab is placed over No. 10, and a red tab over No. 2. The card will not be disturbed on Oct. 10, as the red tab indicates that it is to be removed in a later month, but on Nov. 1, the red tab is removed from the card, and the black tab will bring it to notice on Nov. 10. =Lists of Customers.= Every concern whether it secures business through the mails, by means of personal salesmen, or both, should have a list of its customers properly classified and arranged for easy reference. This should be something more than a list of names and addresses; certain essential facts about each customer--such as his business, the name of the buyer, the credit rating, and amount of purchases--should be recorded. All of this information can be placed at the head of the ledger sheet, but it never should be necessary for another department to consult the records of the accounting department for information needed daily. The information given by the customers' list is of most value to the sales department and should be kept in that department. [Illustration: Fig. 28. Monthly Record of Purchases of a Customer] For customers' lists, cards are most largely used, and are most satisfactory. Cards are readily classified, new names can be added at will, and old names are removed without disturbing the balance of the list or the general arrangement of the cards. The follow-up card can be used as a customer's card, but should be moved from the follow-up to a separate file; or a new card can be made when a prospect becomes a customer.