Repercussions of .htaccess akdlfja

I am completely re-architecting a website that is linked to by quite a few external sites.  

So, I'm using .htaccess to redirect from the old pages to the new pages.

Can anyone here tell me about the real-world implications of doing this?  For example:

1.  Is it better to have one large .htaccess with all the redirects in the root directory, or many small .htaccess files, one in each subdirectory in which a page is being redirected?

2.  In general, how much does redirecting in this way slow down access to any page?  To a redirected page?

If you reply directly, I will get your response more quickly; I am on digest.

TIA,

--Emily
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~                            Emily Berk                                 ~
~  On the web at www.armadillosoft.com *** Armadillo Associates, Inc.   ~ 
~    Internet and non-internet application development, project         ~
~  management, developer relations and extremely-technical technical    ~
~              documentation that developers find useful.               ~
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