Question regarding search

I have a question regarding performing searches. There have been a number of posts here regarding issues with search throughout the development of v3. The response to many of these has been along the lines of “Run File > Save and Rebuild Search Indexes”.

So, my question: is it possible to know in advance of searching if one needs to do an index rebuild? If not then it seems to me that it is hard to have confidence in the search results returned. I.e. if I do a search then do I trust the results are good? Or do I prefix each search with an index rebuild? The latter seems a bit of an overhead, whereas doing the former appears not to be entirely advisable.