What is the best way to sanitize data?

I’ve read several topics about this and different people have different views on the best practice.

In terms of WordPress, how do I write data to the database the safest way?

This is one insert I’m using now:

$result = $wpdb->insert(
    $table_name , 
    array( 
        'arena'         => $galleryData['arena'],
        'year'          => substr( $galleryData['season'], 2 ),
        'copyright'     => $galleryData['copyright'],
        'description'   => $galleryData['description'],
        'path'          => $galleryData['path'],
        'fk_brand_id'   => $galleryData['brand']
    ), 
    array( '%s', '%d', '%s', '%s', '%s', '%d' )
);

Another way of inserting data is doing this:

$sanitized_sql = $wpdb->prepare( "
    INSERT INTO my_plugin_table 
    SET 
        field1 = %1$d,
        field2 = %2$s,
        field3 = %3$s’,
        32, 
        'Aaron Brazell',
        'Washington, D.C'
" );
$wpdb->query( $sanitized_sql );

Do I still need to sanitize data using wp_kses() or mysql_real_escape_string()?

I’m just confused on what method is the better for safely writing data to the database. I found a helpful answer on Stack Overflow.

So should I or should I not sanitize data before input?

No the sanitization is already done. Well the mysql_real_escape_string is done, it’s considered bad form to filter html on input. I personally think doing it on output kinda breaches DRY. If you did in WordPress I highly suspect somewhere else will do it again resulting in double html entities encoding.

Also by the way, wpdb::insert is basically just a wrapper for wpdb::prepare.