How will I know when its time to let the pooch go?

Cerenia

2 of ours just got put down very recently - one had cancer and was going blind, the other very stiff, and deaf. Family decided it was cruel to keep them going in pain, absolutly heartbreaking - had them both within 6 months of each other, for 15 years, the one with cancer due to turn 16 in Jan (i'm 20), so got to say, it was heartbreaking, still upsetting now, but I had many happy years growing up with both of them, and they're not in pain anymore. Will be weird though - going home in 2 weeks, and it'll be the first time there without them Going to be hard, but its best for them.

Think about how it must be for them, as others have said, you know when its time