Browser Refreshing

Question

I notice when building Flash sites on my Mac usually using
Safari, that when I upload an updated SWF that I usually have to
manually refresh the browser and/or dump the browser cache before I
can see the revised file(s) immediately.
I have two related questions...
(1) Is there a certain period on time after which if a
visitor has been to a specific Flash site that it will ALWAYS
automatically update the content to the latest SWFs? In other words
how is this refreshing of content on clients browsers determined?
(2) I have several customer that I have built Flash sites
for. They are all on PCs. They too constantly complain that they
cannot see my updates right after I post them. Once I step them
through how to dump their cache and refresh, they then CAN see the
updates, but their complaint is "What about my customers, they
don't know how to do this and would not even if they could in most
cases. How can I be sure visitors to my Flash site are seeing the
latest content?".

Answer 1

1) I do not see any such setting in any of the Mac browsers?
2) What I am saying is that if I upload a new core SWF to a
server for a customers site to make changes they request, they
cannot see their site changes on their PCs. If I tell them to dump
their cache and refresh their browser window (usually with over the
phone step-by-step instructions on how to do this - since most are
clueless), they can then see the updates I have made for them. But
like they say... none of the visitors to their sites will know to
do this since they will just assume they are seeing the most recent
version when may not be.