I know it's a bit of a technical question and it might not even be that important......

here's the problem:
my client wants to be able to change certain things on the site (as you'd expect) when I'm not around, which is fair enough.
this problem isn't complex enough to require a database, which will just take longer to design so I choose to use simple HTML includes all around the site which he'll be able to edit in the future (using MS Word or something, he's happy about that).

enough crap, here's the question:
can this affect the performance of the website?
if I have loads of includes, could it considerably slow down the server?
please consider extreme situations....

THANK YOU!