The power of habit
If you have read the book, the power of habit, the average person to develop a habit is roughly 21 days. It is the hardest at the first 7 days and after 21 days later, your brain, like a muscle, will be adapted to handle the daily dose of practice routine and willing to ask for more.
This is not just for examination but everything in life, such as exercise, eating habit and etc.
If you think taking 2 quizzes a day is too much for you, make it 1 quiz. The idea is to develop a habit every day and eventually everything will become natural for you.