I wouldn't brag about the battery life on the Nexus 5x, but it's also not horrible. I used to own a Verizon Galaxy Nexus, so I know horrible battery life (two hours of screen-on time, maximum on that one).
I'd say with normal (for me) use, I can get through the entire day on one charge, but it starts to get very low late at night (so close to 11pm, it will be down to 15%). Normal for me is checking social media and email every few hours, playing an hour of games, and streaming the occasional YouTube video. Also syncing up with iTunes using iSyncr. And some random other stuff. Nothing too, too heavy, but I do use my phone (it doesn't just stay screen-off all the time).
The rapid charging feature is handy. If I can get a good ten minutes of charging in in the middle of the day, that does a lot for lasting through the night well above 15%.