Echoing ScottW's last comment about "cleaning", I would cite the article at this web site:
The article on this site is titled "Why I don’t use registry cleaners"
Though it's specific to registry cleaners, and CCleaner is more general, it still applies to cleaning.
An excerpt from that article:
" . . . what possible performance benefits can you get from “cleaning up” unneeded registry entries and eliminating a few stray DLL files? Even in the best-case scenario the impact should be trivial at best. Maybe a second or two here and there, maybe a few kilobytes of freed-up RAM, and I’m being generous. How can you balance those against the risk that the utility will “clean” (in other words, delete) something you really need, causing a program or feature to fail?"
Another excerpt from the same article that really drives home the author's point (and I agree):
"The Registry is an enormous database and all this “Cleaning” really doesn’t amount to much…I’ve said this before, but I liken it to “sweeping out one parking space in a parking lot the size of Montana” … a registry “tweak” here and there is desirable or even necessary sometimes, but random “cleaning”, especially for the novice, is inviting disaster."
And so you don't think I'm bashing CCleaner, here's another excerpt from the same article (which I also agree wth btw):
"I do like the free CCleaner. I’ve cleaned out 1 GB or more of junk on friends computers and it does make the system a little more responsive. You don’t get as many unexplained pauses. This is a problem with the lack of multithreading in Windows Explorer most of the time when it times out on dead resources like a detached network drive. I thought I remember reading something on the Vista features that fixes this by supporting multiple threads.
Other than that, I’ve made sure that I don’t have any dead links the system is trying to access on the desktop that are sure to cause a 30 second lockup even if I drag an icon across the dead link icon. Ccleaner also does a nice job removing a lot of that junk. The combination of MSCONFIG and Ccleaner works wonders."
The author is not saying, nor am I, that some cleaning now and then, like getting rid of temp files, is good and necessary for efficient performance. But I would ask the same question as ScottW . . . "Every 10 minutes?"
Just my two cents on the general topic of cleaning . . .