I thought text search was always the first thing you try, then fuzzy search, then you go for RAG
Volume of documents, size of documents, versioning, frequency of update, documents similar or overlapping information, how much or exactly what you need for the LLM to understand, AI friendly documents, who has access and at what level, blue teaming, red teaming, multi-lingual, does the LLM know the domain language of the user and documents.
I probably missed a few things even with that.
I want fuzzy search like 95% of time and then I might consider having additional list of things that can be suggested by vector search.