Hi there,
I've been formula feeding my 3-1/2 month old from 4 weeks old and I found really quickly that preparing bottles as I needed them was hard to keep up on. I found it very frustrating when I would have a hungry and upset babe in my arms and I'm trying to mix and measure formula. I was able to buy a jug specifically designed for formula mixing. It's made by born free and you can make about 30 oz at once. It has a hand mixer in it that helps cut down on the amount of bubbles in the formula. I mix a jug either at night or in the morning and put it in the fridge. Usually I'll pre-pour a few bottles and keep them in the fridge for a quick grab.
As for sterilized water I have been boiling water in our electric kettle, pouring it into sterilized bottles and putting them in the fridge to cool before mixing into formula. It does take planning to make sure that you have cooled down sterilized water to mix the formula. If the brand you choose also sells small premixed cans I would suggest picking up a couple or a small package for when you're in a jamb. I keep one in the diaper bag and a small bottle at all times in case I get caught up somewhere with no food. It's not like breast feeding where you always have it with you, nice and warm, and ready to go.
For sterilizing bottles I have a microwavable sterilizer that works with a bit of water and just 4 minutes. Right now I'm sterilizing the bottles after each use, but I've read that at about 5 months you can cut back to once a day.
I hope this helps. Bottle feeding is a whole new preparation routine to get used to. In some ways it's easier then breast feeding, but in other ways it is challenging as well.
Good luck,
L
