Are programs a matter of personal preference, or are there certain instances (formal ceremony, church, etc.) where it's expected or more common? I'm having a short, casual outdoor ceremony.
I believe they are a preference. If you want to inform you guests of the schedule of your ceremony, parent's names, officiant name, any peoms you want, schedule after there ceremony then you can use a program to do this. It is an expense you don't need if you're doing a casual ceremony/wedding. You can also inform you guests in other ways like signs, in the invitation, etc.
I'd say they're necessary if you expect guests to say or sing anything during the ceremony, including the "standard" responses at a Nuptial Mass. Otherwise, optional.
Re: Program a necessity or preference?
I believe they are a preference. If you want to inform you guests of the schedule of your ceremony, parent's names, officiant name, any peoms you want, schedule after there ceremony then you can use a program to do this.
It is an expense you don't need if you're doing a casual ceremony/wedding. You can also inform you guests in other ways like signs, in the invitation, etc.