The battery looks to be a classic 300 cycle rated battery. So if you were able to run it down daily that means that it would be hard to hit 2 years.
-> About the non-user replaceable, that's half true. There are YouTubes about replacing it and also companies (here at least) that do this for those that can't crack it open.
I have been unable to find ANY information about the life expectancy of the batteries in the S2 Classic and the S3 Classic. I even called Samsung and not only could they not give me an answer, but they could not tell me the cost or procedure of having the battery replaced when the time comes. All they could tell me is that I could expect to spend a minimum of @ $70 - their customary out-of-warranty service charge. If I'm going to spend $300 or $350 for a gizmo with a non-user-removable battery, I'd like to know the life expectancy, cost and procedure of having that battery replaced. It's one thing to buy an expensive watch for that price that you are going to have for forty years; it's another to spend it on a watch that you'll need to replace in two years. I realize it's wearable tech, not jewelry, but still...
If anyone can help with the info I'm looking for, I'd greatly appreciate it.