There's many a good tune played on an old fiddle proverb
The elderly are still able to achieve/perform astonishing feats.
Despite her old age, she was capable of remarkable feats of endurance. It's true that there's many a good tune played on an old fiddle.
Mr. Bean, who is already one hundred years old, has just finished a marathon. This reinforces my point that there's many a good tune played on an old fiddle.
The origin of this proverb is not clear.