my view (but i'm no vet and not doing great at DB'g either but thats not the point) is that being in the same house means they have much more chance to witness small consistent changes in you BUT (and its a big BUT) i think they also need to see you moving on with your life through GAL'g etc.
For me the main reason to ask them to leave is if it is harming you emotionally more than you can handle or that they are in someway violating your boundaries.
My wife has been at home since BD (early sept 14) and its not been easy, she is now moving out and whilst i know that it will make detaching easier I cant help but feel i have less chance to show an improved version of me.
Both mid 30s, 2 young kids BD 7sep14 XW moved on long ago, now living with OM1 D paperwork in progress