Interpreting sp_BlitzCache: # Executions but since when?
Scroll across to the right side of the results, and there's a &quot;Created At&quot; column. That column shows when the plan first went into the cache. In most cases, SQL Server tracks the execution count since that time - but there can be exceptions in some cases involving recompiles of a query.
The source is the execution_count column in sys.dm_exec_query_stats.