What is the meaning of [Live and learn]

Experience is a good teacher. The longer we live, the more we learn. The
saying is often used in a half-humorous way, as if with a shrug of the
shoulders.

> ‘I bought some walnuts from a barrow – boy in East Street, and when I got
them home and cracked ‘them open, nearly all of them were bad.’

> ‘Ah, well. We live and learn. ‘