I really don't worry too much about things in general, I have the attitude that what will be will be and if you can't do anything about it then don't worry about it.
But there it one thing that does play on my mind all of the time.
Mummy Polly is now approx 14 years old (not sure of her age as she was a stray, but only young when we found her). The other four are 13 years old in May.
At the moment they are all seemingly in good health, in fact Mummy Polly seems to be like a 2 year old.