How long do cats behave like kittens?

How long do cats behave like kittens? I have a 10 month old who acts like a full grown cat and a 7 month old who is a playful kitten. Is there such a difference between 7 and 10 months in age?
When does the average cat start to lose its kittenhood?

I think it depends on the cat, some never grow up!

Sophies 1 1/2 and although she has calmed down from being a kitten, when the two of them play chase it's like the kitten in them is back again

Enjoy it because they grow up too quickly

I've got one who is seven years old and still acts like a kitten!

Sue

Harley is only 4 months old and is my precious little terror-I really think he will always be this way....enjoy them being kittens, they do get big so fast!

Sunni still played like a kitten, even at 5 years old. Sophie, at 5 months, seems to be even more playful than Sunni was at this age. I think I've got an eternal kitten on my hands here now!

I have 2 19month olds, a 7 month old and and a 15 month old that are still mischievous kittens.

I have an 11 year old that isn't above having a daily dorky episode either.

Howdy,

Well I have a 3 year old cat named Hammie who still acts just the same he did when I brought him home at the age of 12 WEEKS!!

He still chases his tail, chases shadows, attacks everyone for no apparent reason, has BOUNDLESS, freakish energy; and is still as fearless and adventurous as I've ever seen him.

I think he's trying to show off for the older cats, really.

Snickers is 14 year old, he's aged physically (losing his sight & lost muscle mass... sort of bony in his old age ) but he is WILD at times, so wild we have to stop him. He runs around the house in this madness and with his bad eyesight & clumsiness --- he careens head-first into barstools, corners, cabinets. Last night he hit his head really hard, during his wild streak through the house!

So some cats are ALWAYS kittens!!!

for one 17 years and counting.... she obviously has slowed down a bit ...

Zoey is 19 month ish and acts like a 4 month old..

Morgie is over 2 years old, and still acts like a kitten!