Line indentation using tabs?

Hi, The comments in the 'users' file mentions lines should be indented with a tab when providing options below a user name. Do all the files require configuration lines to use tabs? Or is does it only matter for user entries? Are lines ignored if they are not indented with a tab? I notice most of the configuration files use hard tabs but I am not sure if this is convenient or enforced. Our coding setup uses spaces to replace tabs, so I need to make sure my deployed files are formatting correctly. Cheers, Dagan McGregor