This condition evaluates true for any database using FULL and Bulk Logged recovery models whose last transaction log backup is more than 4 hours old.
Restricted to SQL Server 2012 and higher
Ignores model, TempDB and ReportServerTempDB databases.
Ignores Read Only databases
Ignores databases in a standby state
Ignores databases identified as a database snapshot
Ignores databases in Simple Recovery mode
Ignores AG databases that are not designated preferred backup replica
Set to check every 15 minutes, evaluates true when last backup is more than 4 hours old