Literally 'practice at eighty' — it's never too late to learn; even at an advanced age one can take up study or training.
祖父は七十代でピアノを始めた。まさに八十の手習いの精神だ。
My grandfather started piano in his seventies. That's the spirit of 'it's never too late to learn.'
年齢を理由に諦めてはいけない。八十の手習いと言うだろう。
Don't give up just because of your age. As they say, it's never too late to learn.
彼女は五十になって英語の勉強を始めた。八十の手習いとは言え、努力は大切だ。
She started studying English at fifty. Even if the proverb refers to eighty, effort is what matters.