How often do my Mac contacts sync with Gmail?
Assuming you've synced your contacts via Address Book then, if you want a deterministic way of syncing in addition to the periodic sync, you can invoke a sync manually from the menu bar app.



OSX is a bit unpleasant in that it will only add this menu item if you set up iCloud, however, you can add this menu to your menu bar without iCloud :) To do so, you need to open a file called Sync.menu located in System/Library/CoreServices/Menu Extras on your install volume (usually Macintosh HD).

You should only need to open this file once and then the menu item will remain on your menu bar until you remove it and should persist through logins and reboots.

If you want a quick terminal command to do the above then fire up Terminal and enter the following:

open /System/Library/CoreServices/Menu\ Extras/Sync.menu