All roses benefit from pruning, as long as it is done properly. While there are some general guidelines for how and why we should prune, the kind of rose you have determines when and how much.
The goal of pruning is to improve the health and/or production of a plant. Dead and diseased/discolored canes (another term for rose branches) should be removed, as well as any branches that cross and rub others, causing abrasions that will invite disease. Also, remove canes that crowd the interior of a plant, which will allow for better air circulation and more light.
Most plants’ ultimate goal is to produce seed, so preventing plants from doing this will often elicit them to try again. Deadheading, or removing spent flowers, will encourage additional blooms in most roses. Fading flowers of rugosa roses eventually produce attractive hips, however, so in late summer they may be allowed to mature.
How you make a cut will have a big impact on a rose’s health and overall shape. Make sure your pruners are sharp so as not to crush the stem. You should clean pruners after cutting diseased canes or before moving to another rose plant. Keep a spray bottle filled with water and bleach (1:1) or water and rubbing alcohol (3:7) and spritz blades between cuts. Cuts should be made just above an outward-facing bud (An inward-facing bud will produce a branch that grows into the plant, blocking air and light and will eventually require removal.) If the plant is in leaf, go down the stem to the first set of five or seven leaves above an outward-facing bud and make the cut there. Cuts should be angled rather than flat, and should be angled to face away from the bud; that is, the high point of the cut and the high point of the bud should be on the same side. This is so water will run off the end and not collect at the bud’s base.
Most roses are pruned in late winter to early spring. The exceptions are Ramblers and once-blooming old garden roses such as Alba, Gallica, Centifolia, Damasks, and Mosses. These bloom on old wood and shouldn't be pruned until after they've flowered, except dead or diseased canes. Hybrid Teas, Grandifloras, Floribundas, and Miniatures bloom on new wood and can be pruned hard; that is, drastically, in late winter/early spring. Remove half to two thirds of the bush, leaving three to five healthy canes. Climbers also bloom on new wood and should be pruned in spring. Cut back the side shoots to about three to six inches long to encourage blooming. Modern shrub roses bloom on older canes, but not so old that they've become woody. Leave these plants unpruned the first two or three years after planting, then cut back by a third in spring, removing the oldest branches. Repeat-blooming old garden roses such as Bourbons, Hybrid Perpetuals, and Portlands bloom on old and new wood, and can be pruned back harder than their once-blooming cousins.