You have to get used to your house constantly being in use and that means it never stays clean.
You have to get used to your workplace, resting place, recreational place, and everything all co-existing in the home
You have to learn how to divide your personal time and personal space which is an craft I'm still trying to perfect.
You have to learn what to do when in order to make for the most productive, peaceful day. When little one's are at home with you, it's strictly about survival.
Learn to use playgrounds and other "free" play areas as a refuge.
You have to know in your heart it is all worth it even when you feel like you are doing it all wrong.