Why do duplicate records appear?
Duplication rarely starts as a decision. Someone copies an address into a spreadsheet to plan a route. Someone else keeps a personal list of pricing. A phone number gets corrected in a text thread but not in the customer record.
Each copy is created for a good local reason. Together they produce a business where nobody can answer a simple question with confidence.
What does drift actually cost?
The cost is not the storage. It is the crew that drives to an old address, the invoice that uses last year's rate, the follow-up sent to a customer who already paid.
Customers experience drift as carelessness. Internally it shows up as time spent verifying rather than doing.
Read anywhere, write in one place
One source of truth does not mean information is hard to reach. The opposite: the same record should be visible in the schedule, on a phone in the field, and on an invoice.
The discipline is about writing. Every fact needs one place where it can be changed, and every other view reflects that change automatically.