Mine was packed around 25 weeks because I kept going into preterm labor but I didn't need I until 40 weeks.
I didn't pack mine until I was 36 weeks... but I had a gut feeling that it was going to be a while and I had her at 40+4. I'll probably pack one this time around 34 weeks, just in case.
I haven't done my yet haha I'm 36/1 but I think I'm doing it today but I have everything ready so now waiting on her to come soon :)
Mine has been almost completely packed since 28 weeks with the exception of snacks for my hubby. Got my diaper bag for my daughter ready already and the car seat is in the car already. I am currently 31 weeks.