Optimistic locking is more appropriate in situations where conflicts are less likely to occur, and the cost of preventing conflicts is greater than the cost of resolving them. Optimistic locking can provide better performance and concurrency, but it requires more complex conflict resolution strategies when conflicts do occur.

Pessimistic locking is more appropriate in situations where conflicts are likely to occur frequently, and the cost of preventing conflicts is less than the cost of resolving them. Pessimistic locking can ensure that resources are not modified concurrently, but it can also lead to performance issues if too many resources are locked for too long.