I wonder what your definition of north and south is? Generally speaking, Hangzhou, Yunnan, Dali and other places are more suitable for health preservation. However, it is cold in winter in Jiangsu and Zhejiang, and there is no heating at home, so northerners may not be able to stand it. The climate in southwest China is relatively constant all the year round, but the problems of urban development and safety may not be as good as those in coastal areas.

What's more, people living in the middle temperate zone and cold zone obviously live longer than those living in the tropics and subtropics, so I suggest you choose to live in a place with four distinct seasons.

If conditions permit, you can choose to live in two places.