One of the crazy feature of upcoming version of Android, Android L, is that it integrates with your Android Wear to automatically lock your phone if you forget your phone somewhere and walk way. While Android L is yet to be released, here is an app which can exactly do the same without it.
Wear Unlock is a simple app which once installed on your phone takes over the lock screen capability with your permission. Once done, you can set up a password which can be used if your watch just ran out of battery or may be you left it behind. Done that, all you need is turn it on and its all set.
To simulate, switch Airplane mode on your watch and your phone will instantly lock. Now turn off the airplane mode in the watch and wait for couple of second so the watch can connect back. Now here is the thing. The phone still displays the lock screen but if you press OK instead of entering your password, it unlocks.
The app costs USD 2 or Rs 120 for India and its totally worth it if you hate putting the password on phone but would love your Android Wear to get this job done seamlessly. Looking at the feedback, the app seems to get constant updates and bug fixes so it gets a must have recommendation from our side.