I also have a 5X. If I'm moving, the battery runs out at about 20% an hour. I normally charge mine in the evening, so it's at 100% at midnight, about 90% in the morning, about 70% after my commute, and around 40% by the evening. It'll be somewhere in the 10 to 20% range by the time I get back home, often with the battery saver active.

During the work day, I generally only use it to check headlines at lunch. I also use it to play back mp3s over bluetooth to my motorycle helmet. The screen is typically on during the day for less than an hour.

The 5X is slower than the Nexus 5 it replaced - 50% more cores but they run slower and most apps take longer to start up. It's a mediocre device and the battery life is not good at all.

Right now, the biggest drains, after screen at 12%, are Google Play services, Android System, Android OS and Mobile standby.

I have a theory that it's Google's appetite for data that kills battery life. They make it hard to use the phone with location services turned off or in battery saving mode except when you want a location in Maps. When you want your location, it gets turned on and stays on. There's no easy way to keep it on to a minimum. I think it's a strategic goal of Google to use customer data for everything from location popularity to traffic, and they're willing to sacrifice customer batteries with nudging defaults to get there.