How long your Operate System run without being reinstalling?

Windows 7 coming up on 8 months now. Probaly reinstall it every 2 years

On my old PC i installed Windows XP when i bough it ... and it was using the same OS for ~7 years i think .

This one is relativelly new just few months ..4-5

Windows 7, installed in February 2010. The thought of reinstalling everything on a new OS install is so overwhelming I can't imagine doing it "just because". So many applications to reinstall, so many VST instruments and sample libraries to reinstall one by one, so many scheduled tasks to re-schedule, so many OS settings to tweak just right...

I only (re)install if I buy a new HDD/SSD (and not always, sometimes I clone the partition), it is not necessary to reinstall if you keep it clean and working fast.

this one's new, running Xubuntu 16.04 since august last year when purchased ssd for my laptop, waiting for my favourite distro next release, will install that than

january 2014, i believe i upgraded from 8 to 8.1, or did a clean install of 8.1. Don't plan to reinstall as long as any unsolvable problems won't show up.

Almost exactly 5 years. I mean to reinstall all the time (as the machine recently really slowed down bad), but I dread the thought of fumbling around with all the necessary programs and tweaks. I guess I'll do it next year, when I buy a new one and this one will get passed on to my son. :)

Windows 7 since 2009 (never reinstall), upgraded to Windows 10 in September 2016 (now I need to perform a clean reinstall).

windows 10 - 03.08.2016, last boot 04.01.2017 but already thinking about reinstall after i will buy windows 10 license.....always something stop working, but i often reinstall windows since windows XP, so cant blame windows 10
as IT guy i do a lot of experiments and i do a lot of stuff on my PC, so it must work as good as possible

Installed Windows 10 same day it was released. Systeminfo shows 15.09, but it was big update not original install date :P Also cloned to other SSD few months ago.
So far Win10 is okey, had few problems with network bridge but no big problems.
Before 10 i used 8.1 and reinstalled it every ~6 months.

The record is held by my 486 DX2 PC that dates from 1999. It runs Win 95 and I never had to reinstall it. I'm not saying I'm still using it but from time to time, for old times sake, I still plug it in to have a look over my old games I made in Turbo Pascal back in the day. For a 66 MHz CPU it deals with pretty much everything ranging from Office stuff to Internet, programming, movies and very old games. Nowadays even my smartphone is an octa-core with more RAM and storage than a building filled with 486s.
My main PC runs Win 8.1 and it's only six months old so it's still in its infancy.

Running since last CPU (and board) upgrade, Installdate March 27 2012, Win7Pro x64 - had to restore an image after an SSD fail once, though... (Learned one thing from it...never ever use cheapo SSDs -like SANDisk- as profile drive...).

Windows 10 since release.

August 2012, Windows 7. What the hell are people doing with their computers if they have to reinstall every 6-18 months?

Windows 7, recently did a reinstall but before that it was about 4 years. SSDs and modern Windows operating systems have really reduced the "windows rot" or slowdown that accumulates over time, but it is still nice to have a fresh install.

Had W7 for 7+ years without reinstalling, then I did clear install with W10.

windows seven running since december 2013, no problem until now so didn't feel the need to reinstall it

Windows 7 pro since 03/10/2012

Windows 7, May 2013, no issues, no reinstall plans :)

Gaming rig -- this past July (new build).
My home server -- October 29, 2011

Windows 7 since January 2013 and it was forced because I moved to a SSD. Not planning to use Windows 10 right now.

15.12.2013. Win 8.1

around 2 years for me but I know a guy who have still original Windows 95 installed on his PC and working fine :)

Running XP that was installed in January 2013 only because that is when I built this computer. I have other computers that have been running XP for over 10 years without a reinstall and with no problems or slowdowns.

I have been using XP for so long and have spent so much time over the years learning how everything works and tweaking it that it still runs just as fast as a fresh install and without any problems. There is no reason to reinstall an OS if you know how to keep it clean.