Carriers charge for any SMS message delivery attempt, even though the message was not delivered. An error in delivery is usually caused when a number is a landline, a VoIP number, a fax line, suspended, or disconnected.

If you can remove these numbers prior to sending to carriers/aggregators, significant savings can be achieved.

If you are continuously sending multiple messages using the same phone number, the savings from scrubbing your numbers can be compounded. Removing suspended and deactivated numbers alone can save you 2~5% of your delivery costs if you are sending three messages a month using the same phone number. Having an effective tool and removing other non-mobile numbers can save you another 3~10% on delivery cost. Here is a super inexpensive tool you can use to remove phone numbers that will never get delivered: www.SubscriberVerify.com.