Installing SEP 12x on Sql server

Hi

I have just installed a sep 12x client on a server which is running sql server.

I have followed the microsoft guide which states the file extensions to exlude e.g. mdf, ldf etc...

I have just added these to the file extension exclusion list but wanted to know if this is the best practice for this as there are a lot of these files i though it was the easiest thing to do.

Does this put any extra overhead on the scanning?

Would it be better to exclude the entire folders or individual files instead of the extensions?

Thank You