Previous preemie moms

I am a preemie mom and with this being my 5th pregnancy but only one living (1 MC, 2 stillborn) her being a preemie (7 weeks early) when should I start to back my hospital bag? Did you prepare for a preemie or waited until you went into labor to have your partner or family by preemie things? I am 31 weeks and my first was born at 33 weeks.