Among one of the earliest questions people learn to answer when studying Chinese is
How many people are in your household?
However, despite living in China for years, I don't recall a Chinese person actually asking this question outside of Chinese class. In fact, if we Google
"你家有几口人？", virtually all of the hits are lessons for non-native Chinese speakers (except for one Bilibili video).
Question: Outside of Chinese class, do people ask 你家有几口人？
For proof of concept, 你好吗？ is commonly taught in Chinese class, yet seldom used (see e.g. YouTube video), so these things exist.