Newbie question on permissions

[William Stephens]

Hello,

Ever since I switched over to Linux (first debian then Ubuntu) I read
everywhere only to use root when you have to and I read about the
praises of sudo in Ubuntu. My question is if I run a few apps that are
run "as root" is that the same as being logged on as root or is only the
app that I am using at risk? Also if I am logged on as root on a
terminal does that risk everything? Thanks for the help.

William S.