Increase php max_input_vars

[jeffryf]

I'm told that including the following line in my htaccess file will increase max_input_vars:
php_value max_input_vars 10000

But when I run phpinfo it shows no change. Others have said that it does.

Since I'm running PHP5 through a CGI script, does this affect php_value?
Action php-cgi /cgi-bin/php53
AddHandler php-cgi .php

[kgc]

When run as a cgi, php directives in .htaccess files aren't used. Why do you need to increase the max_input_vars and what do you actually need in increased to?