Most updates are bug fixes/patches so it'll be hard to tell without looking at the change log in the Play Store. Other than that, you get a notification when each app has been updated and that doesn't go away until you clear it manually
Go to the App Store, upper left hand corner has 3 horizontal bars, touch that, go to purchased. All pending updates appear in a list. In Google Play its "My Apps" in both Samsung stores "Galaxy Apps" and inside Gear Manager Gear Apps, its "Purchased".