I've been bringing baby out very often. Hubby & I will bring her everywhere we want to go. Restaurants, coffeeshops, shopping centres, parks, chalet, club, etc. and also baby spa for swimmng. Mostly by car but mrt/public bus sometimes. Don't think have to wait till 3 months? But I guess going out will become easier as she grows older.
I don't give my EBM stored in the fridge more than a day. Anyway have more than enough, so no reason to give her "old" milk. She usually drinks the "freshest" batch unless if I can't express coz not at home.
My girl juz suddenly begin to sleep through the night last week, after one day when hubby n I went pak tor n left her with my mum for the day. My aunties, cousin, brother & his gf played with her all day and she also didn't sleep after we went to get her. Only slept at 10+ after a feed at night. And the next time she asked for milk was 7+ the next morning! Maybe she was too tired to wake up for milk n after that she probably discovered that it's actually possible to sleep v long with no disturbance. She's like her mum & dad who prefers to sleep than to eat!
I guess u can try keeping baby occupied n awake during the day for a few days so baby tired n sleep more at night. Might get used to it n decide to sleep through.