You will find yourself using your iPhone a lot less, once you've purchased an Apple Watch, according to TechCrunch. The publication has spoken with a number of people who have used the new wearable extensively, and one person even said they "nearly stopped" using their iPhone.
This is because the Apple Watch is built to handle alerts and other matters much more efficiently than your smartphone. Notifications are seen right away and acted on quickly, so they don't pile up, and apparently they're auto-disabled when the Watch is removed or reaches 10% battery life.