As long as everyone involved wants it to last.
My first date with my first wife lasted days. The plan was to have dinner Friday night. After dinner, we wanted it to continue. We went to hers and talked for hours. We decided to have sex, but neither of us had any condoms, so we limited ourselves to oral sex. On Saturday morning, we woke up and had more lovely oral, then I went to my place to shower and get clean clothes, buying a big box of condoms on the way.
I went back to hers later that day. We both left her place Monday morning to go to work. My mother happened to be coming through town Monday evening, and I knew that my ex was going to be in my life for a long time, so I asked her to have dinner with my mom. I was pleasantly surprised that she agreed to meet the mom so soon.
It was literally months before we spent the night apart. We were together for 17 years.