My cat is an old boy, unsure of age but likely to be 18 at least. Approx 5 weeks ago he had pancreatitis, was admitted at vets, treated and recovered very well. The symptons for that were sudden and very apparent - stopped eating/drinking and looks nauseous when he saw food.
In the last few days though his appetite has lessened. He IS eating, but only select stuff, with a preference for human food (see title). He is going to his cat food, only licking the jelly, and not really eating it. He is eating some cat biscuits overnight though. He has pooed and weed regularly so not worried about dehydration - I see him drink water outside regularly. He is purry, his behaviour is normal (currently watching the pidgeons in the back garden). There is no sign of illness as there was with the pancreatitis. He is also eating ham. 
I am giving these human foods in little amounts as I know in theory it's not good for him.
Would you take the vet again? I'm wary of more testing, more staying in, more stress, when they might just say he's old, and slowing down, and this is just start of his decline,.......
Sorry if this is rambled, just would be interested in other stories about care of elderly cats. This is the first time I've had a golden oldie and he's basically not allowed to get ill/die. 