Might it ever be a good idea for retired people to go back to full-time education?

I'd say it can be a great idea for retirees to go back to education, especially when they're learning something practical that connects with their interests. The main value is keeping their minds active while gaining skills they can actually use - like my neighbor in Shanghai who retired from teaching but started taking photography classes. She now helps document community events and even sells some prints online. That said, full-time study might be too intense for some older people - evening classes or online courses often work better because they're more flexible. The key is finding the right balance between challenge and enjoyment at that stage of life.