Err...wanna say a few years for me - started with 10.3, if memory serves. (It's been that long; memory is shot)
Nothing breaks. Correction: PulseAudio broke once because of their issue - it was fixed 45 minutes later in a supplemental patch. That was just PA's screw up.
If you really fuck with package versions, repos, etc...it's possible - but nothing yet here.
And 13.2 will be around for a good, long while.
So...just run 13.2, and avoid the whooping and hollering about Tumbleweed. It (and the new KDE version) breaks a lot of things, and there's no reason to update except being adventurous.
The current versions of oS/KDE right now are rock steady.
I actually think you'll have more effing problems with Debian.
Least with oS, you can go "Shit! I need version 0.89 of this!" and just install/update to that one package, (potentially, if it's not system-wide-dependency) and not have to fight with the computer every damned time you try to just do a software/security update.
And go look at http://software.opensuse.org - need some oddball, obscure-assed program that someone's already packaged?
One-click. Granted, you're a dev, but it makes life a lot easier.
And it's hard to actually build an .rpm that won't behave properly on there, no less - the automated QA stuff is great for users, but annoying for fledgling packagers like me. :p
So, none of the "Well, it's built for Fedora, but I'll try it!" crap if it's on OBS.
I run the thing on a 2007 Dell desktop machine (Pentium-D? 2 GB memory) that lived a happy life in Korea - everything runs nicely.
You'll have a little bit of a steep learning curve again, probably, figuring out YaST, but once you do you'll be putting posters of it on your walls like a kid with muscle cars.
I say try it. Run KDE4 at first - rich environment of programs right off the shelf, and give yourself a week or two to adjust.