Have you ever applied isolation levels higher than read committed?

Yes, higher isolation levels than Read Committed are used when more strict control over concurrent transactions is required to avoid issues such as Non-repeatable Read or Phantom Reads.

For example, the Repeatable Read level guarantees that data read in a transaction will not change until it completes. This is useful in financial applications where it is important that data remains consistent upon re-reading.

Serializable is the strictest level, providing full transaction isolation as if transactions were executed sequentially. It is used when absolute consistency is critical, but it may reduce performance due to locking.

In DevOps practice, setting the isolation level is done in the database configuration, for example, in PostgreSQL:

SET TRANSACTION ISOLATION LEVEL REPEATABLE READ;

Using levels above Read Committed is justified if the business logic requires high data accuracy and is willing to sacrifice some performance.