I don't keep UAC on, because I'm a patient newbie, but instead as an experienced techie with operating systems. Which is unlike those lazy third-party techies who don't understand Task Scheduler, Services, Drivers, SYSTEM processes, sudo, root, CMD/Terminal, etc. And those first 5 are just bypasses by the way.
UAC not only annoys you with prompts, but actually runs programs that didn't need admin rights as standard users. It can work the other around as well, with a password prompt. Not only that, but it provides extra protection for Internet Explorer, and virtualizes the registry of non-shield apps. That effectively prevents non-shield apps from seriously damaging the system in any way, except your profile.
In 2009, this was far more annoying due to Vista failure and lack of program support. Admittedly I used an ingenious method of only disabling the prompts for administrators, but
nothing else back then. Nowadays, it's no problem for average users, real IT techies, and myself.
Then again, I could go serious with third-party modifications like HIPS, system virtualization, instant rollback imaging, and seriously paranoid whitelisting (Firewall, System, etc.) Although they provide arguably higher security (especially questionable in case of HIPS with inexperienced users clicking "remember this"), the user is what counts. That is definitely true for UAC, which is why I only let myself use the administrative account, with everyone else asking me to create a Task Scheduler shortcut or enter my password to try this on their standard account.
What caused me to change is actually yet again laziness. I was very reliant on third-party security that are more complex than UAC, but I still wanted it on for non-admin apps and IE Protected Mode. Now, with a new system and less time, it's time to move on and be more reasonable (especially with
downloads, which are more seriously vetted if origins suspicious).
