Every time a new iOS release went out I've always been skeptical of everyone reporting less battery, I've never experienced it in years, but now I've seen a big degradation of battery life since my last update (from iOS 11 basically). On iPhone 7 Plus I went from 7-8 hours of usage to barely 6.
Usage pattern didn't change much, I basically use my phone for 2-3 hours, just web browsing and a couple of YT videos (when I commute) while during the day I just quick check whatsapp and email. Always connected to my Apple Watch and I listen music (locally stored) through bluetooth headphones (Beats). Background app refresh on just for Whatsapp and FB Messenger. Location is on for Weather, Maps, Uber and another couple of apps.
At this very moment (2pm here in Italy) I am at 62%, 2h 53mins of usage, 5h 44mins of stand by times.
Before iOS 11 I used to reach 60% at 6pm.
Ugrading now to iOS 11.1, if doesn't fix I'll do a hard reset.
Edit: upgrading done (2.15pm here) and I'm at 54%. I'll update this thread tomorrow.