@ LucasM
When the time is right and he's not enjoying life or is in obvious pain, we'll definitely put our old lab down. I thought we were close to being there last week (and it's still likely really near), but a call to the vet and $11 in prescriptions-an antibiotic and an anti-inflammatory- (no vet bill, just a call) and he's doing a lot better. He's walking a lot more normal (still a bit stiff legged, but not struggling to stand or lay down) and is back to playing with our beagle puppy each morning. Yes, he still sleeps a whole hell of a lot, but doesn't appear to be in pain at any time and moves around when he's awake (still gets confused and lost a time or two every day, but that's pretty normal since he went blind).
@ Russoguru
We had a 5 year lab mix that got lymphoma and was given a month to live but lived for almost 2 more years after putting him through chemo. But until his last day (when he got much, much worse very, very quickly) he never acted sick or slowed down at all. Only reason we knew something was wrong in the first place was because he developed some lumps on his neck. Those lumps disappeared and never returned after we started chemo and he never acted sick until the end. Would I do it again? Not sure. It was very expensive, but the reason I'd lean towards not doing it again was not the cost, but the ups and downs of him going into remission several times and that remission always being very short lived. He was by far my favorite dog that we've had (tried like hell to teach my first 2 dogs to fetch but they never learned and he picked it up with very, very little training and I used to spend an hour or more each day and every day throwing a tennis ball to him) and my biggest regret is not enjoying those last 2 years more.