User:NEverett (WMF)/Search Comparison

I'm using this page a a quick and dirty repository of the stuff that the MediaWiki custom lucene-search plugin does compared to what Solr does out of the box.

Questions:
 * How do we know when to update an article in the search index?
 * Certainly when the article is modified.
 * What about when it is linked to?
 * Is Solr's built in spell checking good enough?