When to reach out to stragglers

I would start reaching out tomorrow. Just a simple "hey I was going through our RSVPs and I didn't see yours, will you be able to make it to our wedding?"

I would reach out 2-3 days after the due date since many people put it in the mail the day it's due. I would say "our RSVP deadline was Thursday and we noticed we haven't received yours. Our final headcount is due soon. If we don't hear from you by x-date, we will assume you're not able to make it."

I sent a message out the day of the RSVP due date just basically saying "if you haven't RSVPed yet please do so ASAP, if you have and we just haven't gotten it yet you can ignore this message."

I'd give em a couple days and then I'd reach out

If the date has passed I'd go ahead and reach out to them.

My way of asking: "Hi ------, I was just going over the RSVPs for the wedding and noticed that I didnt have a response from you. I just wanted to check in so we have enough food for everyone if you plan on coming." Always polite but to the point. My FSILs actually got lost in the mail, so I thought she hadn't responded when it just never made it to us and my cousin and uncle forgot to send them back (I had to ask their wives and I thought they were going to burst... they gave them one job apparently).

I would reach out. our RSVP day is tomorrow and i’ve been reaching out earlier just to put it on everyone’s radars! i think just ask “i hope you got our invite in the mail! we were wondering if you’d be celebrating with us?” or something like that.