Anyone that used Windows for a number of years for a number of versions knows that EVERY installations degrades performance over time
Absolutely untrue. I haven't wiped one of my own Windows installs because "it got slow" in at least ten years. Admittedly between 1996 - 2005 I was having more fun doing weird things to Windows and ended up reinstalling a lot of the time, but that's a different story
What does change are the following:
- The base software that almost everyone uses - e.g. web browsers, security software - these get incremental updates and upgrades and steadily their hardware requirements go up.
- A heck of a lot of users don't treat their computer with care, e.g. instead of "oops, I shouldn't have installed that", just don't install it in the first place. Most users don't have the knowledge required to get rid of what's left behind by say a poorly-written browser toolbar uninstaller.
- In the days of pre Vista, a defrag once in a while
- Users installing printers, a printer eventually dies, the user doesn't uninstall the software
- Users inserting the CD from their broadband provider (I live in the UK, foreign providers may not do these things), or a bloody HP printer CD - ending up with a load of crap they don't need.
As a general point, the playing field has altered dramatically in terms of the hardware generally available to run Windows 7 as opposed to WinXP and its predecessors. I am totally in the "tweak it up" camp, but I think it used to make a heck of a lot more difference than it does now. It used to be easy for me to tell the difference between a Win2k/XP-era computer on a stock install and with the Windows filesharing services (and other unnecessary services) disabled. Now the difference is subtle or non-existent. Personally I haven't seen an appreciable difference. A Win7-64 desktop computer build I've done with MSE for security takes about 45 seconds to boot. My own PC is a bit faster, perhaps because it has 4-6 cores (AMD 960T with unlockable cores), but even that is between 35-45 seconds.
My Win7 install is 2.5 years old. If I reinstalled it now, I'd spend hours getting the software I want back on, and its performance would be identical to what it is now. I remember thinking the same thing for my previous build (Athlon XP 2500-3200+) running XP. I really appreciate a fast booting and responsive system, so if I honestly thought reinstalling on a regular-ish basis made the slightest bit of difference I'd agree with you.