Around 90 to 120 minutes total, split across the windows where you have the energy: 15–25 minutes of new vocabulary and grammar in the morning, 20–40 minutes of passive listening on the commute, and 20–30 minutes of review, mocks or writing in the evening.

The morning. Reading new HSK 4 vocabulary at 9am is roughly twice as easy as at 9pm — that is cognitive load, not discipline. Save review, mocks and writing for the evening because their cognitive load is lower.

They measure whether you opened an app, not whether you learned anything. After a few months the streak starts running your habits — five minutes of trivial review at 11:55pm to keep the chain alive. A better metric is how many full mock tests you took this month and what you scored.

Typically 18 to 30 months on an after-work schedule; HSK 6 takes 4 to 6 years. Those are not the timelines apps promise, but they match what people actually do.