I don't have any pets taking it, so I've never talked to a vet about it or researched it, but the talk about glucosamine/chondroitin got me wondering...

-Is the combination of glucosamine and chondroitin really worth the extra cost or is glucosamine by itself just as good?
-Is it necessary to stick to a brand of glucosamine/chondroitin marketed to dogs (such as Cosequin) or is it okay to give a brand that's marketed to people as long as it's properly dosed by a vet?