In many cases, thinking especially of companies in Belgium with a Belgian customer base, this is not necessary at all. Usually, being able to look up addresses in Belgium is more than enough. To go to a mega GIS provider like Google maps or Openstreetmaps especially for this purpose is usually much too big and the costs are much higher. In order not to have to take this into account, we use the GEOpunt and Address Register API of the Flemish government. These are GIS APIs that provide the government with up-to-date address data for searching and suggesting in Belgium.
To give a practical example, let's mention one of our projects: "Vlaams Steunpunt Vrijwilligerswerk - Vrijwilligersverzekering (VSVW)".
The customer asked for the possibility for volunteers to enter their address with an auto suggestion of only Flemish addresses. Admittedly with a failsafe that the moment the API would not be available they could manually enter their address and it could be checked via the address registry API.