I would like to send rehearsal dinner invitations to everyone invited to the rehearsal itself and dinner later on. Our bridal party is a little scattered and seem to do better when they have times, dates and locations in front of them ahead of time. FILs are hosting the rehearsal dinner and have told me twice that they don't think invitations are necessary and people just hear about it from "word of mouth". I disagree and would rather send invites since they are inexpensive and it's not going to hurt anything. I am not asking FILs to buy and send the invites, I will do that. Should I send them or are they really not necessary?