gcc : Is using -Werror and -pedantic considered good practice?

I'm just digging into the gcc manual and some things are still unclear to me:

1. When specifying a std, should I always use -pedantic in conjunction?
2. When using -g, it the standard level sufficient or should I specify level 3, i.e.-g3?
3. Is it good practice to use -Werror to promote all warnings to errors and -pedantic-errors to promote all pedantic warnings to errors?