Sometimes its easier on the animal to put them to sleep, a process which is in its own sad way very peaceful. Watching an animal suffer with tumors or other things is pretty hard to do.
Thanks, MAF. Freeway led a long and happy life, but went downhill VERY fast just before he turned 13. I came home from work early and went with my mom to the emergency clinic, like an hour away, in a snowstorm. My poor baby was severely anemic and would have needed a blood transfusion to live through the night, but his x-rays showed huge masses in his chest cavity. They could have been tumors, fluid, or he could have been bleeding internally. His bloodwork also showed an extremely elevated level of some enzyme or something, and it meant that he was in a great deal of pain. I told my mom that we had to let him go, and we did. I know it was the right thing to do. He was suffering and we didn't want that. He went peacefully.
Homemade Milk, Chronic Renal Failure has nothing to do with your ass. I'm not sure if your question was serious or not, but CRF is when the kidneys shut down. Many cats have problems with this. Melanie is working on about 15% of her kidneys, and I give her fluids under her skin once a week to flush the toxins out of her system. She sees the vet once a month for bloodwork to determine her progress, and since her diagnosis in May, she's been getting better. It's not curable, but it's manageable. My vet's mother actually had a cat with a situation very similar to Melanie's, and it lived for seven YEARS with the CRF, then died of cancer of all things. So I have a lot of hope for her.

When her condition gets too bad though, and when she's not herself and is suffering, I'll have her put to sleep. I owe it to her to not let her suffer a horrible death.
Crystal, is your dog a shih-tzu? He/she is a cutie. Freeway was a lhasa apso and they're very similar. I think both breeds are just adorable.