I like to run programs on my computer to make sure that it is running correctly. I do things like defrag the computer fairly frequently (that reminds me I have to run that tonight!) and I like to check for viruses, spybots, and malware. I also run programs that check for File Extension errors.
If you have a File Extension error, it can cause problems with the Registry, and can cause some files to not open, or work properly. In some cases a corrupted File Extension can cause your computer to work slower or crash. So checking the Registry often for errors, and correcting them when you find them is a good idea to maintain good computer health.