Give people the complete contact
Publish all ten digits and use a click-to-call link on mobile pages. For an international audience, show +1 followed by the ten-digit number; callers still need a plan that supports the call.
A neighborhood name can orient a visitor, while a street address tells them where to go. A 202 number alone does not distinguish Georgetown from Dupont Circle or Downtown.
Be clear about time
Use “Eastern time” beside your opening hours. A live regional clock is useful to customers calling from other time zones; a fixed UTC offset can become misleading when daylight saving changes.
Decide what someone should hear outside opening hours. A concise greeting with the business name, hours, and next step is often more useful than publishing another unexplained number.
Review every place the number appears
Before a changeover, list your website, directory listings, booking messages, stationery, and signage. Update them after the new line has been checked.
Test an inbound call from outside your own phone system. Confirm that the caller reaches the intended department and that any separately configured voicemail or messaging works.