At the last house we had a bamboo and although we had a very small garden we bought the biggest we could afford in order to give impact in the garden. It wasn't planted in the ideal location, but once it settled in it grew every year very well and every winter I would give a prune to show off its coloured stems. When we moved it was not a plant I could have dug up easily and brought with us, so we bought another for the current garden.
The current plant is about four years old and it does have a tendency to send out a runner once in a while. The first two years I let the plant be and last year was the first time it had a trim. I have done the same again this year. Basically I have completely removed all of the thin straggly stems from the plant by cutting back to ground level. then for the remaining stems the bottom two to three feet of each have been stripped of side shoots. This enable the bamboo to become a feature plant during the winter months, with the coloured stems singing out, especially if caught by the evening sun.