hey
having the chains done has shown improvements in engine mpg and nippiness 🙂
vauxhall stated that 10 year or 100k miles for the chains change interval if they have not been done or you're concerned that they have not been done getting them done would be peice of mind for the future
there are some parts of the chain kit that are plastic and as we all know after time plastic can become brittle i believe this is the reason vauxhall set the 10 year interval