Friends are of two types – the Jewellery Type and the Clothes Type. The Clothes Type friends lose color, fade away, grow small etc with time. While the Jewellery type friends are inert. They don’t react or change with time and age. They don’t lose color, they don’t fade. In short, you don’t outgrow them and they don’t outgrow you.
BTW, people without friends are more likely to die an early death. So go out and find your friend!