Before you take that walk down the aisle, sit down with each set of in-laws and talk about boundaries within your relationship.
For example, when a couple considered purchasing a house close to his mother, the mother-in-law said, "I am okay with you living close to me, but you will call before you come to visit and I will do the same." That was one smart mother-in-law!
Things To Consider
If your in-laws have a key to your home, how will they use that? Are you okay with them dropping in whenever or is the key for emergencies only? AND, how do you define an emergency?
Is there an unspoken expectation that you would come over for dinner once a week?
How do you feel about your spouse talking with his/her parents about issues within your marriage?
Do they expect to talk with you every day?
How will you handle unsolicited advice?
What are your in-laws' expectations surrounding holidays?