One other thing to add - in the case of 'non-standard' pets (so pretty much anything other than dogs, cats and rabbits...), educate yourself. You will often get much better results if you can go to the vet, tell them what it is and why you think it is that, and tell them what treatment is normally recommended for that condition.
Some treatments (notably antibiotics) are prescription only, and do require a vet visit, even if you know exactly what is wrong.
I used this technique when I had 'productive pet' chickens - back in the days when no one kept them as pets! Indeed, I often found myself educating the vet... hopefully it's not usually that bad with hamsters, but educating yourself in advance can never be a bad thing
