Upgrading to FC5

[Jim Lowman]

Hello,

I've been running FC4 on a dedicated AMD64 box,
and also on a laptop, and have downloaded and
burned the ISOs for both the i386 and AMD64
versions of FC5.

Is it always recommended to do a clean install,
or would choosing the upgrade option on
installation suffice?  

Between versions I use yum upgrade to stay current.
Do I really need to download and install the newer
version of FC?

Sorry for the newbie questions.  I'm trying to
make the transition from Windows.

Thanks in advance...Jim