Some time ago I described the query fingerprint and query plan fingerprint (a.k.a. query hash / query plan hash) features that were added in SQL Server 2008. A fingerprint identifies all queries or all plans that have the same “shape”. With query fingerprints you can get the cumulative cost...

Explicitly parameterizing queries is a well-known best-practice for database app developers. There are cases where it can make sense to execute a query unparameterized, but, in general, you should default to explicit parameterization. It can make your queries faster by avoiding unnecessary compilation...