There are many basic services that I think are essential to anyone living in a home in the city. One of the most important I think is a plumbing service. I suggest having one of these on stand-by should anything happen to your own plumbing.
There are all kinds of services that fit a variety of problems, scheduling, and even budgets.
Many even include payment plans for the more expensive work. many even have a 24-hour service if you have an emergency that can't wait. Either way, they can work with your needs when you have a plumbing issue.
I think that having a plumber that you trust is important. It is also important that they are near to you and affordable. This will cut down drastically on waiting time to get things taken care of in case a plumbing issue occurs.