As a former pastor I know that one of the key decisions for a Christian is "choosing a church." Therefore I have included a helpful article done by Mark Roberts on this subject. Let me say this, once you become part of the body then you need to stay attached to the body. Of course exceptions apply for example:
1. God calls you and family to a ministry not provided or supported by your local church. Also God may call a person, couple or family as missionaries.
2. The preaching and teaching have fallen into a form of heresy.
3. The leadership has an obvious violation of integrity and they have gone through proper Biblical confrontation but will not hear or repent.
There may be other reasons but they don't come to me at this point. However it is my experience that people come and go in regard to church like they buy a TV, computer or automobile. In America when people attach and become member they just reattach to any other church as it fits their own definition based on what they want. Unfortunately they rarely see the wake of devastation they can leave behind especially in a small body of believers. And when asked why they left, often the problem that they saw in the church they were not willing to be involved in the solution. There was a couple in our church, Joe and Mary Smedley that came to me complaining about the nursery for their grandchildren. When I asked their adult children and themselves to brainstorm, propose a solution and get involved in this ministry using their gifts, they got offended and left the church. Seriously that is what happened and these people, most Christians would consider, "seasoned" and "mature" Christians.
Well with that as a preliminary ramp up, here is the article on "choosing a church" - Part 1 and Part 2.