What do significant others do during ceremony rehearsal?

I’ve always seen them just hang out in the ceremony space until everyone transitions to dinner. I think it would be inconvenient for them to take extra cars.

I’ve done both. There was a wedding where I just hung out and watched the rehearsal. There was another one where I just came to the rehearsal dinner. I’m letting the S.Os choose what they want to do for my rehearsal

Whatever you want them to be doing. Invite them or don't invite them. We're having them either be at the rehearsal with us in the background or they can wait at the resort bar/dining room until we're finished.

We are leaving it up to the significant others what they would like to do. Our rehearsal will be at the same hotel everyone is staying at, so they have the option of coming down and watching the rehearsal, going to the hotel bar for cocktails, or the spouses calling them when it’s time to come down to leave for dinner.

At mine they kind of just hung around haha.

FH's has two brothers both are married. His oldest brother's rehearsal I just hung around and watched the rehearsal out of the way, second brother I planned to do the same thing (I was super involved with second brothers wedding, so the plan for me was to assist with letting the venue know where the décor went) but second brother's wedding was cancelled last weekend due to the hurricane that was supposed to hit CT (they still got married at their would be rehearsal dinner).

For mine, I'm leaving it up to the SO's, we haven't decided where the rehearsal dinner is going to be yet, or what night of the week the rehearsal is going to be since we're getting married on a Friday, but everyone is local so the SO's can decide if they want to come to the rehearsal or just meet us at dinner.

Many hang out at the venue and watch the rehearsal as a guest and others meet up at the dinner. It’s all personal preference.

At a friend's recent wedding all the SOs sat in the back of the church during the rehearsal. At my sisters, they hung out inside the reception area which is also where we had the rehearsal dinner (everything was at one location)