Explanation

Box 1: stats_date
See example below.
Box 2: rowmodctr
See examplebelow.
Box 3: stats_date
You need to identify statistics that have not been updated for a week.
Box 4: rowmodctr
You need to identify that more than 1,000 rows changed.
Rowmodctr counts the total number of inserted, deleted, or updated rows since the last time statistics were updated for the table.
Example: We will query every statistics object which was not updated in the last day and has rows modified since the last update. We will use the rowmodctr field of sys.sysindexes because it shows how many rows were inserted, updated or deleted since the last update occurred. Please note that it is not always 100% accurate in SQL Server 2005 and later, but it can be used to check if any rows were modified.
--Get the list of outdated statistics
SELECTOBJECT_NAME(id),name,STATS_DATE(id, indid),rowmodctr
FROM sys.sysindexes
WHERE STATS_DATE (id, indid)<=DATEADD(DAY,-1,GETDATE())
AND rowmodctr>0
AND id IN (SELECT object_id FROM sys.tables)
GO
After collecting this information, we can decide which statistics require an update.
References:
https://docs.microsoft.com/en-us/sql/relational-databases/system-compatibility-views/sys-sysindexes-transact-sq
https://www.mssqltips.com/sqlservertip/2628/how-to-find-outdated-statistics-in-sql-server-2008/