Fit indeed seems to be the source of the problem. Funny thing is that I had seen Fit's battery usage get pretty high, so the first thing I did was uninstall it. At that point Google Services skyrocketed - almost like it took on whatever battery was previously listed as Fit. Yesterday, I reinstalled Fit, then cleared its data and rebooted. That didn't seem to do a whole lot... Play Services battery usage decreased but Fit was back on the list, so that the sum of the two was similar to what just Google Services was using previously. I then went into Fit and disabled the Activity Tracking setting, then for good measure deleted Fit's data and rebooted. I haven't touched Fit since yesterday and battery levels seem back to normal so far. So it looks like something to do with Fit as well as its Activity Tracking. Like N4Newbie, I also wear the Urbane, if that adds some sort of data point (ie. in determining if it has to do with Fit + Wear, or simply is Fit's fault?)