Recommended number of index for a table

I've a table with many columns (~70) which contains computer's configuration. It contains approximately 50 000 rows.

This table is very requested and all these column too.

I use to run the following query to know missing index history:

-- Missing Index Script
-- Original Author: Pinal Dave (C) 2011.

use myDatabaseName

SELECT TOP 25
    dm_mid.database_id AS DatabaseID,
    dm_migs.avg_user_impact*(dm_migs.user_seeks+dm_migs.user_scans) Avg_Estimated_Impact,
    dm_migs.last_user_seek AS Last_User_Seek,
    OBJECT_NAME(dm_mid.OBJECT_ID,dm_mid.database_id) AS [TableName],
    'CREATE INDEX [IX_' + OBJECT_NAME(dm_mid.OBJECT_ID,dm_mid.database_id) + '_'
    + REPLACE(REPLACE(REPLACE(ISNULL(dm_mid.equality_columns,''),', ','_'),'[',''),']','') +
    CASE
    WHEN dm_mid.equality_columns IS NOT NULL AND dm_mid.inequality_columns IS NOT NULL THEN '_'
    ELSE ''
    END
    + REPLACE(REPLACE(REPLACE(ISNULL(dm_mid.inequality_columns,''),', ','_'),'[',''),']','')
    + ']'
    + ' ON ' + dm_mid.statement
    + ' (' + ISNULL (dm_mid.equality_columns,'')
    + CASE WHEN dm_mid.equality_columns IS NOT NULL AND dm_mid.inequality_columns IS NOT NULL THEN ',' ELSE
    '' END
    + ISNULL (dm_mid.inequality_columns, '')
    + ')'
    + ISNULL (' INCLUDE (' + dm_mid.included_columns + ')', '') AS Create_Statement
FROM sys.dm_db_missing_index_groups dm_mig
INNER JOIN sys.dm_db_missing_index_group_stats dm_migs
    ON dm_migs.group_handle = dm_mig.index_group_handle
INNER JOIN sys.dm_db_missing_index_details dm_mid
    ON dm_mig.index_handle = dm_mid.index_handle
ORDER BY Avg_Estimated_Impact DESC

GO

But for these specific table it gaves me twenty different indexes with an impact > 300 (impact = dm_migs.avg_user_impact*(dm_migs.user_seeks+dm_migs.user_scans)).

I read somewhere that it's not relevant to have more than 10 indexes, is there any recommendations about it and how can I know if it's really usefull to define all these indexes?