The Gear S3 may see a battery bug after the Tizen 3.0 update according to a growing number of users who are claiming to have experienced increased battery drain following the installation of that new software. Not all users have experienced this problem with their watches after installing the Tizen 3.0 Value Pack update, but if you're worried about the battery drain issue coming up and you don't want to risk it surfacing, and if you haven't already installed the update to your watch, then you may be better off waiting to install the software until it's clear that Samsung has a fix that it is ready to push out to users, which may not be something that happens very quickly as it's been a couple of days initially since users first started reporting this problem and it doesn't seem like any details regarding a fix have been announced yet.
All that said, if you have already installed the Tizen 3.0 Value Pack update then you can always do a factory reset to perhaps help with the issue in some form, though it's likely that nothing will really fix the problem that isn't a software patch from Samsung itself.
If you missed what the Value Pack update included and you're not too worried about battery drain anyway, then installing the Tizen 3.0 software may be worth your time as it does included quite a few goodies and software improvements through the addition of new features. One of the main goals with this software update for Samsung was to help streamline the information for the watch wearer. This happens in a number of ways with the update, from viewing and editing contact information right on the watch to getting new details for fitness-related information at a glance. The software even lets you sync the watch to your Samsung smart TV and control fitness programs that are being streamed to it via the smartphone that your watch is connected to. If you tend to watch fitness programs in the home then this might be something you'd love to use, in which case, battery issue or not the software will have some uses and some value for you. In the end users will still want to keep an eye out for the patch, as Samsung may end up sending out a patch soon.