Disk Utility as Maintenance?

I know I've asked a lot of questions lately but, well, that's why we are here right .

I've had my iMac since October and have of course added different types of software as well as installing all system updates without any problems. But after reading different posts and articles I've learned that you should repair permissions after installing software that requires a installer, and at anytime BEFORE a major system update.

Now, I'm not sure if any of the later are considered "major", but I certainly meet the criteria for the former.

So should I go ahead and run disk utility for the heck of it, and if so can it be run from utilities, or do I have to use my SL disk to perform the task.

Thanks

P.S. I searched the topic but nothing really hit the mark.