Formula moms!

Do you have tips for travelling with formula/preparing bottles ahead of time for easy access? I'm still breastfeeding but have been starting to supplement as well, at home during the day it's easy to prepare a warm bottle but going out is less easy for me. breastmilk bottles are fairly straight forward, they're good in the fridge several days and can be at room temperature for 4 hours. Formula is trickier! Tips are appreciated 😊