From middle school to high school I had a dog named Ranger. He was a chocolate lab and he lived to be incredibly old, 105, roughly, if you accept the 7:1, Dog:People year ratio. It was really one of those classic Boy-and-his-Dog scenarios, sure Ranger was the family pet, but he thought he was mine. We got Ranger when he was a little older, so I always knew in the back of my head that time was limited, but I didn't think about it, eventually I almost forgot about it.
Eventually Ranger got sick. The vet said it was a tumor. We were told it would most likely cause Ranger to die, but it might not. Still, the vet told us most likely Ranger's condition would deteriorate and we could choose to put him down now, or hope for the best, at least enjoy what time we had left with him.
At first Ranger seemed completely normal, we'd play in the backyard, he'd hop up on to my bed at bedtime, where ever I sat he'd be within arms-reach. Eventually, however, Ranger's condition started to deteriorate, just as I was told. At first he wasn't interested in playing anymore, which was expected so I spent more time on the little things, belly-rubs etc. Soon enough I had to start helping him with the things he loved to do, I'd lift him on to my bed at night, help him get into the car to go for rides. A time later he would spend most of the time laying on my bed, this period became very hard on me, I loved Ranger and even though he was still there he wasn't himself. It was really hard, I knew he wasn't doing well but I knew he was still happy to be with me, and I was happy to still have him.
The time came to put Ranger down. It was a very difficult thing for me, I wanted to keep Ranger with me, more than anything, but I knew he'd only keep getting worse, keep getting harder on me, on both of us. Afterwards, even now when I think about it, I wonder if it wouldn't have been better to put Ranger down before things started to go down hill. He was still happy, I was still happy. Sure, we got a few more months together, and I know we still made each other happy during that time, it was hard to watch him slowly waste away like that.
To this day I don't know what the right decision was, or even if there was a "right" one. The regret of drawing it out to squeeze what happiness we could out of the last little bit, or the mystery of what could have happened if we let him go at the beginning. It's one of those things I try not to think about too often.