Random Spotlight Malfunction


I would like to know if anyone else has been faced with the following issue:

I use spotlight all the time to navigate my hard drive and quickly start up apps. Every so often my spotlight will fail to initiate a search for keywords. When this happens, I have to go to the Spotlight Privacy Preferences, add my HD folder to the list, wait a couple seconds, and remove it from the privacy list to force spotlight to re-index my hard drive. This would not be so bad but it take a few hours to index the drive and usually when I use spotlight, its to find files that I am looking to work on ASAP.

One oddity is that I can't determine the trigger for Spotlight to stop functioning. It just seems to happen randomly and is NOT due to updates, installing/un-installing, file removal, so on.

Is this a common issue with everyone? Is there any maintenance procedures that I should do to keep my HD properly indexed all the time?

By the way, I am running a 12.1-inch Powerbook G4, 1.5 GHz, 1.25 GB RAM, OS X Tiger.