What date should be on the RSVP?

There is no set rule on what the rsvp date for an invitation should be. The potential guests need at least a week or two to figure out if they will be able to attend. You need to set a date that allows you to properly prepare for the event based on how many guests are coming. Depending on the event the rsvp date could vary from a couple days before to a couple weeks or even a month before.