One extra space or a lowercase keyword gives you a second cached plan. See it in the cache, and learn what actually fixes it.
Why Queries Recompile
Why queries recompile becomes clearer when you capture Extended Events causes and check schema changes, statistics, SET options, and temp tables.
Comparing Session SET Options Between SSMS and the Application
Fast in SSMS, slow in the app? The query may be fine and the connection settings different. Here is how to check, with nothing to set up.
Plan Cache Key Lookups: Finding the Worst Ones With XQuery
Not every key lookup needs fixing. Rank statements by reads, find the lookups with XQuery, then test the smallest index change on one call.
Caching Query Results in the Application
Caching query results in the application can reduce repeated reads when ownership, expiry, invalidation, and memory cost are clear.
SEQUENCE Cache Size, Gaps and Insert Throughput
Compare SEQUENCE cache size, restart gaps, rollback gaps, and insert throughput with CACHE 50, CACHE 1000, and NO CACHE.
DMV Snapshot Deltas for a Query Activity Interval
DMV snapshot deltas show counter growth for cached statements that survive two observations. Compare their identities and report missing coverage before ranking activity.