Powdered supplements for dogs

[Joani, Skadi & Elli]

Has anyone recommendations for powdered supplements for dogs.  Looking to extend life, Skadi will be 9 and Elli 10 next year.  Elli still energetic but has benign tremors in leg.  Skadi had cruciate ligament surgery when 2 years old.  Both very healthy otherwise.  

[Nancy, Ned, Clancy, and Charlie]

I have no medical knowledge but I know my dogs are getting all the vitamins etc from their high quality kibble. What I have added is Dausequin ( probably misspelled) as a joint supplement. Ned and Clancy are 10. Charlie is only 5 but he has joint problems already. 

[DonMarie and Picco]

I'd say as long as they eat healthy, that's the best you can do.   Too bad dog cloning cost so much.