Making bottles in advance?

Hi there! newbie here... due in Nov. I always see posts about how annoying it is to make a bottle in the middle of the night, etc. This is probably a dumb question so my apologies, but is it against the rules to like make a ton of bottles in advance? Like make a few days' worth of bottles and then just use the bottle warmer when needed? Or do they go bad very fast? TIA!!