A table has many indexes but INSERT and UPDATE operations are slow. How would you troubleshoot it?

First measure the write workload and inspect all indexes on the table. Every relevant INSERT, DELETE, and key/included-column UPDATE may require SQL Server to maintain multiple index structures.

Use index usage statistics to identify indexes with high user_updates but little demonstrated read value. Look for duplicate or overlapping indexes, unnecessarily wide INCLUDE lists, poor clustered-key design, page splits, foreign-key requirements, triggers, constraints, and transaction blocking.

Then evaluate read and write workloads together before consolidating or removing indexes. The correct objective is not the fewest indexes possible; it is the smallest set of indexes that provides required read performance without imposing unjustified write and storage cost.