When do I need to re-build my index files?
Index files should be rebuilt about as often as web content changes. Your should rebuild your site's index file whenever you update your site's content. For general web index files, rebuild them about once a month.
Also, whenever you make a configuration change that would affect what the index holds, you may want to rebuild. Possible configuration changes would include:
- Changing the set of "ignored words"
- Changing certain field sizes, like "Max Characters: File" or "Max Characters: Title"
- Changing the set of web pages in the Forbid Sites or Promote Sites group
In general, configuration changes will apply to all *new* records added, but they don't apply to existing records. Thus, to benefit from the performance gains of having a low "Max Characters: File" setting, the existing index files would have to be rebuilt.
"When do I need to re-build my index files?" http://www.xav.com/scripts/search/help/1037.html