Matthew McGiffen gives us the numbers:
SQL Server has had the ability to automatically update statistics since version 7.0. Nonetheless for a long part of my career working with SQL Server, whenever a performance issue raised its head everyone’s knee-jerk response would be “Update Statistics!” In most cases though the people shouting that didn’t really understand what the “Statistics” were, or what mechanisms might already be in place for keeping them up to date.
Of course SQL Server isn’t perfect and sometimes it is helpful for human intelligence to intervene. But to provide intelligent intervention one has to understand how things work.
Read on to learn what triggers automatic stats updates in various versions of SQL Server.