I'm on 10.1.1. Battery life is ok for a 15 month old phone with a heavy user. I'm in the 78% to 80% battery health range. I might make it to September.
I get about 7 to 8 hours usage, depending on what I do. Sometimes less than 7 when I'm working with images and photoshop.
Keep in mind the big 3 battery users are Screen brightness, push notifications, and location services. So keep your screen brightness as low as you can stand it. I keep mine about 30% inside. I turn it up outside. I use as few notifications that use push as possible. I don't need push notifications from all my apps. Most are turned off. The same with location services. Very few are turned on. Most "while using app". "Share My Location" will use a lot of battery. Many of those in "system services" use battery. I keep most of those off. A few are necessary. If you use Facebook, turn off Location services. If I want to show where I am, I enable location for that, then turn it back off. Also in Facebook settings, turn off video auto play.