Assign people tables, but let them sit wherever at their table. Don't let people sit wherever because you might end up with people dragging chairs over to tables and over crowding or having people sit by themselves
I would definitely assign tables! However, I wouldn't assign specific seats at those tables so that people can sit by who they want. If you don't do any assigned seating at all, guests will either be confused, or you'll need to provide extra tables and chairs, since people don't really seat themselves efficiently on their own.
Team assign tables! I went to an open seating wedding and it was really annoying. Cocktail hour was in the reception space so people claimed seats right after the ceremony, but my family and I had to stay behind for pictures, so we had to split up.
I also think a seating chart is the best option. Allowing guests to sit themselves isn't as simple as it sounds. Guests don't natural sit in groups 8-12 people so you will end up guests moving chairs or some tables overcrowded and other tables with only a few people sitting at them. Or like my husband and I experienced at a wedding you'll have guests tell other guests that seats are taken because they are saving them for someone else. I personally hate going to a wedding that doesn't assign tables.
If you have more than say 20-25 guests, assigned tables are an absolute must. Otherwise, groups will start getting split up and things get chaotic. No need for assigned seats unless you are hosting a formal event.
Seating chart or place cards 100%. We were going to skip that, but after attending a wedding that didn't have one, we quickly changed our minds.
We, and a group of our friends showed up a little early for the ceremony (we had all RSVPd as well). The ceremony seating was already filled and there were people standing behind the last row of chairs already, so we had to go to the second floor to overlook the ceremony. Cocktail hour was outside with no chairs as well, then we came in for the reception with no seating chart or place cards in sight. We entered in behind most of the other guests and literally every table was taken. Uneven groups would take up a table leaving 1 or 3 seats open, making it impossible for couple's or our friend group to sit with/close together. Our group, and several other people ended up having to get our food AND eat standing up. Basically, the whole entire day was spent on our feet lol and I was NOT happy because I was wearing heels. It was a dang nightmare, and upsetting considering that we all RSVPd and didn't even get a dang place to sit the entire evening.....
Escort cards with table assignments unless you are serving desserts only in the afternoon. Otherwise there will be pandemonium with couples/families split up, people who should not sit together are forced to, etc and everything is reminiscent of the high school cafeteria with only random single seats available.
I used to think I would just assign tables, but I think im going to assign seats too. I went to a wedding recently and people don't naturally sit next to strangers. Say there are 3 couples assigned to a table. Couples 1 and 2 leave an empty seat between them. Couple 3 gets in late and now the whole table has to readjust. I never thought about it before but I think it's easier if you want to fill in tables.