yum update

[Gene Poole]

I started using yum to update my systems as-soon-as 'up2date' was no longer
supported.  So, I have friends and people I work with asking me for a 'rule
of thumb', which I don't know.  So, I'm asking the member of this list:

   What is the 'rule of thumb' for re-booting after the completion of the
   'yum -y update' command? How do you know if you should re-boot - if
   there is a kernel update? Should you reboot based upon what key
   components have been updated?  How do you know what's been updated if
   you schedule it to run at 2 AM?  Do you ever have to re-boot?

I don't have a answer to these questions, do you?

TIA,
Gene Poole