i do things differnt , i have cold boiled water in the fridge and also use hot water from the kettle ,, when my baby wants a bottle i make it up half hot half cold so that theres no time in waiting , it works for me he gets his bottle as fast as it takes to boil the kettle

with both our sons we pre-made bottles, and i used the stove later.

i found it easier for me this way, as i'm kinda noisy in the kitchen and didn't wanna wake my wife...

it worked for me :-)

but when we're on the go during the day, i find it easier to keep round a couple of bottles of room-temp water, and do the powder thing. (we usually use liquid formula not powder for his regular feedings)

-peace

Personally, I hated my bottle warmer.  At 3 am w/a screaming baby it felt like hours before the bottle was ready in the that thing.  I found it easier to prepare the water & mix in the formula later.  Also, nothing gets wasted if baby doesn't wake up for all her night time feedings.  I also just used room temp. water.  If you noticed breast milk isn't real warm, just warm enough, it doesn't feel like it just came out the microwave & hot water heater, so my baby that went from breast to bottle prefers her bottles at room temp.  Try everything & see works for you!

it depends on the temperature that you give the bottle at i never warmed my bottles so they stayed at room temperature. as long as the powder isnt added to it and the lid stays air tight on the bottle then it is still sterlised. I just added the powder as and when needed. it proved handy when going out and about as you can buy the containers to store each section of milk and then add as requried.  you can do this before going to bed then all your powder is measured and you just tip into bottle shake and give to baby.

The formula I have been using and I have used 3 different kids they all say you can store them up to 48 hrs (2 days) It is alot easier to prepare them ahead of time and put them in the fridge after you have prepared them! It don't take long, I use the liquid stuff instead of the powder, it's a little more expensive but well worth it. As for warming up the bottle, it all depends on the type of bottle you have, either it can go into the microwave or you can just leave it under hot water in the sink.. That's what I do right now, if you do decide to use the microwave, MAKE sure to shake it before you give it to your baby, because it could be very hot and hurt your baby. Always make sure the bottles are warmed up to room tempature or even a little warmer than that, but not screaming hot.

I found that when I i prepared my daughters bottles it was much easier, however, they only keep for 24-36 hours, depending on which formula you are using. Also I would not reheat bottle more than once... I did heat my little girls bottle twice and it was ok, but wouldn't recommend this until a later stage!
Also, when the baby is older, say 7 months old....presuming bubs is only 8 weeks old? I would stop preparing the bottles....only prepare the water.... and put the formula powder in as you need it!