Old as dirt.

Forty is the old age of youth; 50 is the youth of old age.

Old as the hills.

Life is half spent before one knows what it is.

Older than dirt.

There are toys for all ages.

The old gray mare just ain’t what she used to be.

The old forget, the young don’t know.

Old age and treachery will overcome youth and skill.

He who wants to warm himself in old age must build a fireplace in his youth.