Q. 1. My family just moved into a different city. There are a number Catholic Churches in this city. At what Church should we attend Mass?
A. 1. Every Diocese sets a geographical area that is associated with a particular Church. Traditionally, when a Catholic (and family) moved within that geographical area, they were associated with that Church/parish.
Nowadays, in many Dioceses, especially in the West (Americas), almost nobody does this anymore. They choose to worship where they feel the most spiritually uplifted.
Such a determination can be based on the priest (his preaching, liturgical abuse, his personal beliefs versus the Church teaching, etc...), the music, the average age of the parishioners, the Church activities, etc...
This freedom of choice has resulted in the closing of many Churches. As the number of worshippers dwindles, the parish being unable to financially maintain its Church, it comes to an early end. The life of the Church depends on its worshippers.
Ask not what the Church can do for you; ask what you can do for the Church!