cozie - well, this is on my mind a lot too - yes, she's generally very happy and has turned into a sweet, purry, cuddly old thing, having been quite cantankerous in her youth. Loves her food, loves cuddles, still plays a bit, still goes out once in a while, likes a catnip mouse as much as the next cat 
But -
She sometimes does the yowling at the wall thing but is fine as soon as you pick her up. I do wonder though what happens if we are all out and she has a 'lost' moment when there's nobody there to reassure her.
She's not keeping herself as clean as she used to. We spend a lot of time brushing her and going over her with those grubby pet wipes but she's still a bit pongy.
She had a seizure a few months ago. We took her to be checked over after that and the vet said she's in extremely good health for her age. She's had no further seizures and doesn't appear to be any worse for it.
Then there are the practical issues. As well as the peeing issue, we can't all go on holiday at the same time any more (DC are adults living at home so not as difficult as it could be) - I wouldn't feel comfortable leaving her. It would also be a bit much to expect neighbours to clean up all the messes.
We also have a massive and growing list of desperately needed home improvements that we can't start on because it would distress her - she's never been good with change.
But yes, I'd say she's a happy cat