PostgreSQL indexing is essential for achieving peak performance, especially when dealing with large datasets. A well-designed index can accelerate data retrieval operations, enhance query performance, minimize disk I/O, and enforce data integrity. However, over-indexing can lead to storage space consumption, maintenance overhead, and slow write operations. To optimize PostgreSQL indexes, it's crucial to identify unused or underutilized indexes, monitor shared_blks_read and blk_read_time metrics, and regularly review and optimize indexes. Additionally, updating statistics after adding or removing an index is vital for the query optimizer to make better decisions. By following indexing best practices, such as only indexing what's needed, avoiding low cardinality columns, and testing and benchmarking new indexes, developers can create efficient and effective indexing strategies that enhance their PostgreSQL database performance.