Defining Files locally in Sub-Procedures - What advantages has everyone found doing it that way?

Our shop is going to be moving from V5R4 to V7 in a few months so I can
finally start using the enhancements in V6 and V7.

The idea of being able to define the files in Sub-Procedures instead of
globally in a module I was thinking would be very cool. Then I got to
thinking when would I really need to do that? When has everyone else been
finding it was a better idea to define the files in a sub-procedure?

I was reading about how the file will be closed without it having the
static keyword. When would it be better to use the static versus not? If
your using the sub-procedure repeatedly the open and closing of the file
seems like a reason to be using the static. Interesting idea that you could
be getting different records for the same file in different sub-procedures.

Thanks
Andy