The login.defs file
 

I was wondering if the settings in the the /etc/login.def supercedes the settings that are defined in /etc/shadow for individual accounts.

If the setting in login.defs says every user has to reset their password every 60 days but the shadow file says 10 days, who wins this?

Point me to any documentation saying this?

Chris

login.defs is what the system looks at for creating new accts.
Current accts will have whatever they are currently set to ie /etc/shadow.
See chage http://linux.die.net/man/1/chage to change the latter.