A script to answer: Should I use SPARSE?

CREATE PROCEDURE usp_identify_sparse_candidates
@SchemaName SYSNAME
,@TableName SYSNAME

AS
-- author: Jeff Reinhard
DECLARE @TableRows BIGINT
DECLARE @CommandRows INT
DECLARE @ColumnCounter INT = 1
DECLARE @SQLCommandTable TABLE (SQLLine INT IDENTITY (1,1), SQLCommand VARCHAR(MAX))
DECLARE @SQLString VARCHAR(MAX)
DECLARE @ResultsTable TABLE 
(SchemaName SYSNAME, 
TableName SYSNAME, 
ColumnName SYSNAME, 
NullCount INT, 
PercentofRows MONEY, 
SparseThresholdPct INT,
SparseRecommendation CHAR(20))

SELECT @TableRows = SUM(p.rows) 
  FROM sys.partitions AS p
  INNER JOIN sys.tables AS t ON p.[object_id] = t.[object_id]
  INNER JOIN sys.schemas AS s ON t.[schema_id] = s.[schema_id]
  WHERE p.index_id IN (0,1) 
  AND t.name = @TableName
  AND s.name = @SchemaName
GROUP BY s.NAME, t.NAME

INSERT INTO @SQLCommandTable (SQLCommand)
SELECT  'SELECT '''+@SchemaName+''' as SchemaName, '''+@TableName+''' as TableName, '''+COLUMN_NAME+''' as ColumnName
,COUNT(1) [NullCount]
,COUNT(1)/'+CAST(@TableRows AS VARCHAR)+'.0*100 as PercentofRows
,CASE '''+DATA_TYPE+'''
WHEN ''bit''THEN 98
WHEN ''tinyint''THEN 86
WHEN ''smallint''THEN 76
WHEN ''int''THEN 64
WHEN ''bigint''THEN 52
WHEN ''real''THEN 64
WHEN ''float''THEN 52
WHEN ''smallmoney''THEN 64
WHEN ''money''THEN 52
WHEN ''smalldatetime''THEN 64
WHEN ''datetime''THEN 52
WHEN ''uniqueidentifier'' THEN 43
WHEN ''date''THEN 69 
WHEN ''datetime2''THEN 52
WHEN ''time''THEN 60
WHEN ''datetimetoffset'' THEN 49
WHEN ''decimal''THEN 42
WHEN ''numeric''THEN 42
WHEN ''vardecimal''THEN 42
WHEN ''varchar''THEN 60
WHEN ''char''THEN 60
WHEN ''nvarchar''THEN 60
WHEN ''nchar''THEN 60
WHEN ''varbinary''THEN 60
WHEN ''binary''THEN 60
WHEN ''xml''THEN 60
WHEN ''hierarchyid''THEN 60
ELSE ''UNKNOWN''
END as SparseThresholdPct
,NULL as SparseRecommendation
FROM '+@SchemaName+'.'+@TableName+'
WHERE '+COLUMN_NAME+' IS NULL;

' 
 FROM INFORMATION_SCHEMA.COLUMNS
 WHERE TABLE_SCHEMA = @SchemaName AND TABLE_NAME = @TableName
 AND IS_NULLABLE = 'YES'
 AND DATA_TYPE NOT IN ('geography','text','geometry','timestamp','image','ntext')

SELECT @CommandRows = COUNT(1) FROM @SQLCommandTable

WHILE @ColumnCounter <= @CommandRows
BEGIN
SELECT @SQLString = SQLCommand FROM @SQLCommandTable WHERE SQLLine = @ColumnCounter

--SELECT @SQLString
INSERT INTO @ResultsTable (SchemaName, TableName, ColumnName, NullCount, PercentofRows, SparseThresholdPct, SparseRecommendation )
EXECUTE (@SQLString)

SET @ColumnCounter=@ColumnCounter+1
END

UPDATE @ResultsTable
SET SparseRecommendation = CASE WHEN PercentofRows >= SparseThresholdPct THEN 'Yes to Sparse' ELSE 'No' END

SELECT * FROM @ResultsTable
ORDER BY ColumnName

GO