Is there a general rule of thumb/ percentage of people that will RSVP no to go buy. I have 175 listed but will 175 make it, no? I know some will RSVP 1 instead of 2 or wont' be able to make it..but how do I know when making my A-list/B-list confirming room for X amount of people.  Do I confirm the venue with amount of people that I am inviting, HELP i'm sooo over analyzing this! hahaha.