In late summer, after flowering, it is a good idea to prune the main stems of species, shrub, miniature and rugosa roses lightly (by up to one-third) and reduce sideshoots by one-half to two-thirds.
For renewal, cut out up to a quarter of the oldest flowered stems.
Whenever you are pruning roses it is a good idea to wear protective gloves as the thorns can cut and scrape you easily.