Not true at all. The battery isn't replaceable, other parts are more likely to break, and it's not clear to me that the Apple Watch even has a high quality quartz crystal inside it for accurate time-keeping. It might simply be grabbing the time off the linked cell phone, which grabs the time off the cell network. Do Apple Watches work well independently of linked phones for months on end? Years? Because that'll be necessary if you want to keep using one decades down the line long after they're no longer supported by whatever phone replacements have come down the line next.