my baby is 12 days old and I am supplementing with formula as I don't produce much breast milk. this might be a stupid question but I'm a FTM and can't seem to figure it out. we have a doctor's appointment today and id like to bring a bottle with us as baby might get hungry but we often end up waiting in the doctors office for a while and I know once you make a bottle it only lasts an hour. I have seen people leave the house for longer then an hour with there babies so there must be something I'm missing. how do you take bottles out with you when you leave the house??