At age 16, after several months’ illness. At the vet., because despite treatment it had gotten difficult for him to breathe even when resting, and that stage might have lasted for some time.
Survived by his sibling, two other feline friends, and a number of human friends including me, who will miss him.
By my standards 16 is too young. I can usually get cats to somewhere between 17 and 20.
I’m so sorry. Peace to you and your feline pals. 
I’ve lost two cats at age 18. That still isn’t long enough. 
Hugs to you and yours.
poor kittycat. It’s always sad. But good that he had Human Friends looking after his last days and making them peaceful.
Truly, it sounds as if he had a long, wonderful life. I’m glad you had him, I’ll give my Atilla extra scritches in his memory. I’m glad you have other pets for consolation.
Yes, in my experience, 18 is the age when most cats start packing up for the trip home to Bast.
I’m sorry yours left early. You made the right decision though.
Thanks, everybody.
nearwildheaven, you’re right: it’s always too soon. I’m glad he stayed the other couple of times in his life that came close, though.
I’m so sorry, thorny. Losing a beloved kitty is always hard.
So sorry to hear of your loss, thorny.
Shine on, you crazy feline.
I’m so sorry,** thorny**. 16 isn’t old at all.
I’m sorry Thorny. You’ve mentioned your kitties several times over the years, and I’m sorry you had to say an early goodbye.
Thanks, everybody.
Vet. sent quite a nice sympathy card. Picture on it looks a great deal like Sleek and Shiny’s still-living sister when she was younger; minus the white tip on the tail.
I’m sorry for your loss. 
I’m so sorry, thorny.
I’m sorry for your loss, thorny. It’s never easy to let them go, no matter how long they stick around.
Mine generally don’t make it past 14…we’ve lost 4 since we started having cats–one at 5 of lymphoma, and the others at around 13-14 each. I’m really hoping our remaining four (two age 10 and two age 14) stick around longer.
I’m so sorry. There must be a cat-shaped hole in your heart right now.
Thanks again.
It’s odd how a house with three cats in it can feel so empty of cat. Indeed, like there’s a hole there; though one that moves around, to his various Usual Places.
– Infovore, apologies if I’m bringing up something here you already know about, but just in case: if you have an older cat who seems to be failing do you get them checked for hyperthyroidism? It’s extremely common in older cats and can present with few or no symptoms other than gradual weight loss; many people think the cat’s just getting old. It’s treatable, in most cases, with a small and not very expensive pill twice a day, which can often buy two to four more good years.
We have one cat who has hyperthyroidism, and that’s what happened–she just kept losing weight although she was still happy and eating/drinking/etc. We treat her now with stuff we smear on her ear twice a day, and she’s gaining weight. Oddly, her meow has changed - now she sounds more like she’s quacking! Don’t know if it’s the meds or just her getting old.
Of the other three we lost, two had cancer and the third had kidney failure. I still feel guilty about not catching it sooner, but the vet told us it’s hard to catch until it’s far along because they are great at hiding it. Still feel guilty, though.
I’ll have to tell my vet that there’s another report of voices changing! Both Sleek and Shiny and his sister were/are on thyroid meds; and both of their voices changed – hoarser, and to a sound that sounds more like a complaint, though I eventually figured out from context that it had just become their ordinary meow. (Sister just came in and illustrated in the middle of my typing this post; translation turned out to be ‘Come open the door! I want to go out!’) Not sure whether it’s the same thing that you’re describing as a quack. I told the vet., and she said it was the first she’d heard of it. I’ve had another cat on the same medication, and his voice didn’t change. I don’t know whether it’s the medication or the thyroid growth itself that’s causing it, or even something else going on.
– and your vet’s right, they are really good at hiding illness. And both cancers and kidney failure are pretty common; though the kidney failure often not until they’re older, but it does develop in some cats much sooner than in others.