Multi-generational living

A small prediction: with the rise of healthcare in this country families will be choosing to live together to save money as a multigenerational family. We are already thinking this direction. My mom is not getting any younger and she wants us to purchase a home together. It's got me thinking about the pluses and minuses of families living together.

Plus:
Saves families money
Multiple families can share accessories/appliances/etc ie: freezer, lawn mower, food processor
allows for all members of the family to help care for the children (it takes a village, right)
Saves gas (run errands together, store, pharmacy etc)
Allows for more interaction with family members
Take turns cooking (yay me!)

Minuses
You have to get along.
Not everyone always lives the same way (one cleans and the other does not place importance on cleaning)
Personalities can clash

Well it looks like I have more pluses than minuses. We are seriously considering moving this direction. But I do worry about being in between my husband who has some OCD tendencies and my mother who could care less about cleaning anything. If anything happens I will be the one in the middle. So I'm not sure how/if we can work it out. We've talked about putting it all on paper and agreeing to terms. But you're not going to think of everything are you?

Anyone else got any pluses, minues, or ways they've dealt with being a multigenerational home? Please chime in and tell me your story!