htaccess File Help

[alfuzzy]

My server setup has multiple .htaccess files (which I'm guessing may be normal).

Server setup is public_html directory...then forums sub-directory. Both the public_html directory & forums sub-directory each have a .htaccess file.

My questions are:

1. How do each of these .htaccess files work together (if they do)?
2. Should each of them contain the exact same information...or should the higher up public_html directory have less/more info...or should the lower sub-forums directory have more/less info in it?

I'm sure I will have follow up questions...but wanted to get these 2 out of the way first.

Thanks