How should I properly trim spruce trees to maintain their health and appearance?

To properly trim spruce trees for health and appearance, prune dead or damaged branches in late winter or early spring. Use clean, sharp tools to make clean cuts at a slight angle just above a bud or branch junction. Avoid cutting into the branch collar. Remove any competing branches or those growing inward. Do not remove more than 1/3 of the tree's total foliage in a single season to prevent stress.