Map the first answer
Write down what should happen when someone calls your main number. Who answers first? Does the behavior change by department, business hours or location? Start with the customer experience rather than a list of features.
Think beyond the desk
Identify people who answer from mobile devices, home offices or field locations. Ask suppliers to demonstrate the actual workflow on the devices your team would use.
Account for exceptions
Include unanswered calls, holidays, transfers, direct numbers and any special-purpose lines. Alarms and elevators require their own qualified review; do not treat them as ordinary business extensions.
Plan the changeover
Ask suppliers to verify number-porting eligibility, equipment requirements, training and the implementation schedule. Keep your current service until the approved transition is complete.
Compare a complete proposal
Look at users, devices, add-ons, implementation, support and contract terms. Confirm emergency-calling setup with the selected supplier. The right solution should fit the way your people handle calls, not just an attractive introductory price.