Re: 3 months old - how much per day?
Baby's weight is a better indicator of how much formula to offer than age. How much does your LO weigh?
Also, boiling water is unnecessary in most cases. Unless you have well water with a risk of bacteria in the water, you probably shouldn't boil it. With public water, boiling can actually do more harm than good because it will increase the concentrations of heavy metals in the water.
Christian WOHMama to DD1 7/07
and twins DD2 and DS 11/11