As an on-site service provider, it would be incredibly helpful for customer/project and vendor addresses to be automatically synced to the favorite locations list for automatic mileage tracking. Obviously not all QBO Mileage Tracking users would need this feature enabled, so it should be added as an option in the Milage settings menu.

The name of the favorite location would be the display name of the corresponding contact. To improve clarity, perhaps a small icon should be added to the beginning/end of the display name to indicate that this is a synced location of a specific type, and not a user-entered one. The icons for the customers/projects and vendors pages in the menu list would be perfect - I've attached a screenshot to illustrate.

If two contacts share an address, or are in close enough proximity that the app cannot tell, the user should be prompted to choose between the possible matches similarly to how bank transaction matching works.