Pruning, in general, is an excellent way to rid your plants of dead, unruly, or unwanted limbs, and many plants absolutely love this yearly “haircut”!
Clematis vines are among these; after the large, weaving vines produce their summer stock of purple, blue, or white flowers, etc, the woody limbs are usually in desperate need of an autumn trim.
Keep in mind that although clematis is a hardy plant and easy to maintain, certain species of clematis require pruning at different stages of the year, so check out your specific vine before whacking it back.
If you are comfortable with after-bloom, fall pruning, do not be shy about cutting your clematis down fairly close to the ground. This removes all the dead, damaged, and ailing branches, allowing the roots and short stalks to explode with growth when spring comes again. However, If you are more satisfied with pruning in the spring, feel free to wait until then.