Criteria used to select a partner for search?

Hi everyone -- I'm beginning to get the search bug and still deciding on parameters such as going solo or partnering up. For those who worked with a partner: Did you have any criteria to decide that you two could handle the emotional toll that ETA can take, both pre and post-close?

I recently listened to one of Will Smith's old Acquiring Minds podcasts with Jessica Markowitz. She mentioned multiple discussions and tests she and her partner did to ensure they could maintain their friendship through the process.

I know every search is different, but I'm curious if there are things you (partnered searchers) did to make sure you both could handle this journey together.