One

The 1-10-100 rule is a quality management concept developed by G. Loabovitz and Y. Chang that can be used to illustrate the costs associated with missing or incorrect data. 

It’s pretty basic really - prevention is better than remediation. The cost of $1 to sort address data before it enters the system is money well spent. Correction at the halfway point could cost 10 times that - simply using manual processing to sort and correct the data. The 100 times factor occurs when the delivery fails, causing redelivery costs, customer service team interaction and an adverse effect on brand reputation and future loss of sales.