Better every day
How do you get better at doing something? You practice it every day. How do you know you have practiced enough for that day? The same way a Mormon tithes. A fixed percentage of your time, every day, is enough to help you improve. I cannot say what that percentage is going to be, it’s different for each activity. But it should be enough that it is a difficult goal to achieve, but achievable by those that want to reach their goal. 1% of your day for good health. 2% of your day for extreme fitness. 2% to 4% for a creative pursuit. 10% if you are insane and 20% if you want to build a million dollar income.