I've seen lots of posts about this subject, but no answer resolution yet. I bought a Z10 two months ago and tested it for one weeks without a SIM card. Everything was really fine and battery duration was superb. When I installed the SIM card and started using data services the device started overheating (not the battery) draining the battery completely in about 4 hours. This phenomenon appears especially when I am roaming. When roaming I also noticed that data services seemed to "disconnect" although I had a good signal, for and browser and other applications would not work as if I had not Internet access. I have checked out and am absolutely sure that this is not happening due to an app. Have seen lots of users complaining about this but there is no clear answer: is this a firmware problem or hardware defect? Has anyone resolved that?
Since you have no other replies, I'll provide my perspective.
I have no way to know if the problem is firmware or defect, but what I can share is my controlled testing results. I tracked, day by day, the resulting battery percentage over the course of many weeks. In that time, a relatively consistent degradation started at about day 9 every time...sluggish performance, battery draining quickly, etc. In each case, I rebooted and the problem was gone...until another 9 days passed. Consequently, I reached the conclusion that rebooting about once per week would be a healthy action to conduct...YMMV based on your own usage patterns, etc.
Note carefully that all of that testing was done under the 10.0.x.x OS. I have recently updated to 10.1.x.x, and have only re-started my controlled testing, which shall take several weeks to conduct. As such, I have no answer as to if anything is improved or degraded under 10.1 in this regard.
Note carefully that these devices are not mere "phones"...rather, they computers that just happen to also do mobile telephony as part of their functionality. As such, they are subject to all of the foibles that plague computers -- memory leaks, badly behaving apps, etc. etc. etc. Consequently, when thought of as a computing device, rebooting once per week isn't really all that bad IMHO.
Occam's Razor nearly always applies when troubleshooting technology issues!
If anyone has been helpful to you, please show your appreciation by clicking the button inside of their post. Please click here and read, along with the threads to which it links, for helpful information to guide you as you proceed. I always recommend that you treat your BlackBerry like any other computing device, including using a regular backup schedule...click here for an article with instructions.