Discus live for as long as you give them the right food & clean water.
Asian breeders & the such, practises are mainly just to breed pairs, pump out the young & collect $$$
Therefore they pump them full of blackworms, beefheart mix, blood worms & the like. They get a couple of great years of breeding out of them, the discus by then are shot, then they just get rid of them so to speak.
If you look after them with water quality & diet then getting 5-10years out of them should be no worries at all.
Aussie dosen't have the meds available like in the states, there are some discus around here over 10years old.
Its more a case, watch what you bring into the tank. If your food is clean & healthy, so is the water. Why do you need meds? As is care when introducing new tank mates.
Yep they seem to be more prone to some parasites & diseases, but I think that is direct link to food types, eg; to much live black worms,{parasites} blood worms & beef heart{hex & bloat}....etc
I see some sites suggest bombing discus with worming tablets once every now & then. You shouldn't have too.
After all, discus are just a cichlid.
Frenchy