Each and every cat on the planet has an unique personality. With adult cats it is much easier to make a match between you and your new cat.
Healthy cats live longer than 15 years, so a six year old cat still has a decade of love to give.
Cats are so independent, adult cats easily adopt caring humans.
Adult cats usually already have some trained habits and are fully grown they do not need as much attention as kittens and can be left on their own when you are at work.