Which changes will break a job

Hi Guys
Testing bacula and i was wondering about what the Subject says
Which changes will break a job(by Break i men the job will fail and u
need to create a new job to have the new setup) aside from stuff like
Changing Storage client and device, i was thinking about stuff like
changes in schedule(i.e different days on diff or full backups,
changing hours), pools meaning changes VolumeRetention, Job retention
etc
Anything else that will cause a working job to fail in the way of
changing Jobs set up

Regards /Mehrdad