Which practice helps manage index maintenance costs over time?

• A. Never modify indexes once created.
• B. Always create indexes on all columns.
• C. Regularly review index usage and adjust or drop unused indexes.
• D. Indexing should be disabled in production.

Answer: (C)

Regularly review index usage and adjust or drop unused indexes. Indexes speed up reads but add maintenance cost for writes and extra storage, so as workloads change over time some indexes may become unnecessary or duplicated. By monitoring how often each index is actually used (and analyzing query plans), you can prune those that aren’t helping, keeping performance strong while reducing maintenance overhead and space usage. The other approaches are too extreme: never modifying indexes fixes them in place even when they’re no longer helpful; indexing every column wastes space and slows writes; and turning indexing off in production removes the speed benefits for queries.