It's also important to note that conifer branches should never be pruned past the foliage area. Most conifer branches, as they extend from the truck, have several inches of bare wood. These bare sections have no latent buds. Make a cut in this no-man's land and your branch will eventually die. But most conifers will do just fine if the pruning is done with care.
Early summer is the best time to control size and shape.
Making your cuts after new growth is completed has a slowing effect on conifers, which is why many gardeners prefer to prune them at this time of year.