Nowadays people are very slack in responding to wedding invitations. So don’t take it personally if by the time of your RSVP not everyone has replied! You therefore need to have your RSVP date early enough to give you time to personally contact those you have not replied.
Most will say ‘of course I’m coming’. But unless you’re psychic I don’t know how they expected you to know! You can reduce the stress around this time in a few ways. Consider sending out reserve the date cards well in advance of your formal invitation, particularly if your wedding date is in a holiday period or near a long weekend.
Following up those who have not replied may also be a task you can give to someone else – maybe a bridesmaid. The important thing to remember is that people will want to go to your wedding – many will just forget to tell you!