One number, or several: how to decide and what it costs

Split numbers when different people answer them or when the traffic has different risk. Do not split them to look bigger - each number is another session to monitor, another quality rating, and another place a customer's history can hide.

The two good reasons

Routing for free

The number a message arrives on is the best routing signal there is, because the customer already made the decision when they chose which number to write to. It beats keyword matching and it never misclassifies.

Blast radius

Promotional sending is what gets numbers restricted. Keeping it away from the number that carries order updates and support means a bad campaign costs you the campaign rather than the business.

The costs, which are real

• History fragments. The same customer messages sales in March and support in June, and nobody sees both unless the inbox joins them by number.
• More to monitor. Each number has its own session that can end silently.
• More to publish. Every number on every signboard, invoice and website, kept in step.
• Customers pick wrong. Some proportion always will, so every number needs somebody who can redirect - or, better, an inbox where redirecting is not needed.

A rule of thumb

1. One number until two different teams are answering.
2. A second when promotional sending starts, deliberately separate from the transactional one.
3. More only per branch or per market where the answering is genuinely local - a number per product line that one team answers is administration, not routing.

Whatever you choose, publish it consistently

The most common failure is not the split. It is three numbers on the website, a fourth on the invoices, and a fifth that a former employee put on a listing site four years ago - and that one still receives messages nobody reads.