When would you use a Hashed Index vs. a standard B-Tree index?

Choosing between a hashed index and a standard B-Tree index in MongoDB depends entirely on your query patterns and data distribution requirements. Standard B-Tree indexes are the default and most versatile type, optimized for a wide range of operations including equality matches, range queries, and sorting. Hashed indexes, on the other hand, are a specialized tool designed primarily for two scenarios: supporting hash-based sharding and performing equality lookups on fields that are typically large or have poor B-Tree selectivity.