In what cases is it recommended to create indexes in a database to speed up queries?

Indexes in a database are recommended to be created in the following cases:

• Columns that are frequently used in WHERE conditions for data filtering.
• Columns involved in JOINs between tables.
• Columns used in ORDER BY or GROUP BY for sorting or grouping.
• Columns that are often searched or queried with high selectivity.

Indexes speed up read operations but slow down insert, update, and delete operations, so it is important to create them consciously, based on actual queries and load.