How often should OS X be reinstalled?

Mate, again, it's just not necessary. I format and reinstall for each major upgrade (Tiger to leopard and so on), and that's it.

 

The only time I'd recommend reinstalling OSX is when/if your hard drive goes belly up and you have no choice, or you have some other serious problem which cannot be solved in any other way -- which is rare. Probably never.

 

The beauty of using Mac, not defrag to do, no virus scan to worry about and no registery to clean up. I am a very heavy user, (graphic, web design and development) The one and only installation on my almost 3 years old G4 mini was when I first bought it. Re-installation? What's that?

 

sure it's needed sometimes... wehn you tweet out the OS too much like I used to.

 

2 years is more frequent then I would like to, after all, I didn't re-install my XP for 4 years.

And I don't think 2 years reinstallation is necessity. Just stay with old OSX, skip one or two upgrade here or there. Its not that crucial for most people, and software compatibility problems might take long time to sort out(maybe long enough for you to skip it altogether)

I also agree that there is less things you are allow to tweak in OSX, or few people do that if that makes any difference.

 

Windows I had to re-install every 6 months. For the same reasons as the OP.

OSX - unless it is noticeably slower - or buggy (panics / beach balls) - then leave it as-is. (something disk utility can't fix up)

I can't imagine there is a time limit - unlike XP with its "freshest if used only 6 months".

I've been running OSX 2 years - and it's fine. I did an archive and upgrade with Leopard - so it's somewhat starting with a new plate. But Tiger wasn't performing any worse than I could remember, prior to my "upgrade".

 

I went to my local store and bought a copy of XP when it was released. I installed that copy on a Dell XPS desktop and it's still going strong (I later gave the PC to a friend) without a single reinstallation! File-system fragmentation was a problem but not nearly so great as the defragmenter sellers would have you believe. My wife's 2-year-old PC has not had a single XP reinstallation, either (it's got a firewall and protection from viruses and malware; so, it hasn't even fallen victim to those).

OS X is a superior operating system, founded on (fairly) rock-solid Unix with the addition of Apple's ease of use. I enjoy my iMac more than my former PCs because 'it just works' and is much more intuitive (in the main). OS X can stand on its merits - there is no need to denigrate XP or any other OS. I often wonder whether people who attack Windows are trying to convince themselves. Vista may be best avoided but XP really is pretty good: you can admit that - after all, OS X is simply better.

 

Even reinstalling Windows every six months seems excessive in my humble opinion.