I remember the days of iOS 5 and my iPhone 4 where my battery would last ages. I use a golf score app that gives me yardages to the hole using GPS. I used it for a year before iOS 6, and after each round of a fully charged battery, I'd have ~70% battery left. Now, it's ~30% with iOS 7 and my iPhone 5.
My usage has always been the same. What's changed is newer and less efficient versions of the apps I use and what Apple lets these apps do in the background. Even with background refresh turned off, I still get crap battery life.
I'm not checking my phone more, or using it more, it's purely the apps I use that suck the life out the battery. I lose 1% a minute sometimes just by browsing the web, then chatting on Facebook Messenger.
Apple really needs to implement battery life rules for apps they approve. It's a really big problem, and it's no good Apple's ad campaigns showing off how good the iPhone is and all the available apps when you can barely get a day's usage out of it.
2 day battery life should be their target, and they can start by being really strict on inefficient apps they approve.