Seating Chart?

After otherwise you'd have no idea who is actually attending.

I have had an idea as to who will be attending and who won’t so I started creating table seating a while ago, but of course it changes. The rsvps have slowly but surely been coming in so my guests have less than 3 weeks to make a decision because once I complete my final seating chart, that’s it! Lol I just don’t want to get stuck doing anything last minute

You can always start creating it earlier for some of your definites. You’ll obviously have to go back over it when you get the final headcount

I’ve made a rough draft and will adjust as the rsvp choices come in.
It allowed me to plan ahead and see who I could intermingle and who I had to keep separated due to personality information from my FH. Also gave me a rough idea of how many tables we will need to set up and consequently how many centerpieces I can plan on arranging.

You can do a rough draft now, but I wouldn't finalize anything until you have all your RSVPs otherwise you've wasted a lot of time.

I would wait until after you have your final headcount, since everything could change drastically based on RSVPs. Like others suggested, if you want to start on it now, maybe start doing a rough draft, and update it as guests RSVP?

I have a ruff draft on my phone that I add to as rsvps come in. Right now it’s really just grouping people together and then once our rsvp deadline has passed I will fill in tables as needed

I did it after. It took my husband and I like 2-3 hours in 1 night to do it. We wrote everyone's names on index cards and then assorted them into piles (which would be tables). Then we played around with where those tables would go.

After. I made a rough draft on paper with table assignments. But we did not have the final chart made until we had our final headcount in.

I did a rough draft as the RSVPs went along but it was finalized after

I started mine when I made my guest list and then deleted people off if they declined. I only had to move a few people in the end. Most of my tables had 6 people at an 8 top. So everyone had plenty of room!

I actually started making a rough draft of seating chart before just to look at how many tables I would need, because there are people I wouldn't be able to seat together.

Had a general idea in my head then edited after we got the guest count

I've created a rough draft so that I have an idea of the number of tables needed, and to just have an idea of seating arrangements in general. Of course nothing will be finalized until guests RSVP.

I bought a huge poster board and drew our tables on it, then bought a bunch of mini post its and wrote names on them as people RSVPed. I was able to start it knowing 30+ guests attending (family, wedding party, etc.) then finished the rest as people RSVPed.

As others have said, you can start doing a preliminary draft whenever, but wait as long as possible to make the final chart.... In the best of circumstances there can be last minute changes, with COVID, it seems like they are the norm. The last thing you want is to get it all done early only to have to re-do it the night before. For that reason, daughter chose to do escort cards rather than a seating chart. The morning before the wedding one of my cousins texted to say her husband was ill, but asked if it would be okay to bring her teenage daughter. We'd already paid for the meal, so were fine with the change but it made more sense for the daughter to sit with other teenage cousins rather than with her mom and other middle-age aunts & uncles -- a few quick table assignment changes were needed. I think I wrote out a total of three new escort cards and was done -- easy-peasy!

You can get a head start on it by grouping people together. Then make your final draft when you get the rsvps in.

A sample of how to put one together:
https://somethingturquoise.com/2011/09/02/diy-easy-seating-chart/