When you go to Open a family file in Revit, it will make a difference as to where you select the Open command as to what folder location Revit will default to select the file.
If you choose the Open… function from the opening screen of Revit, Revit will default to the location of the specified Revit Library Path. (This location is specified in Options -> File Locations -> Places.)
If you choose the Open function from either the Quick Access Toolbar or the Applications menu (big R at top left of screen), Revit will default to the location where you last saved a family file.
While this is not major information, it is handy to know when you are opening a family from one location, making changes to the family, and then saving it to another location.