it would be expected that a needle evergreen would lose needles from the interior, a season of growth at a time. I would check for spider mites as possible cause and consider that weather patterns the past several seasons have not been typical and a greater loss of needles is possible. Make sure the evergreens are well watered, don't wait for a doughty period to show up. Water well late into the season ensuring soil moisture is available as you enter your winter months. You can fertilize in the spring when plants are actively growing. Lastly older plants can suffer more and react differently than younger plants
