In a given time period, let's say a year, you may personally work harder or smarter than in some other year. Do you believe that you should be compensated the same regardless of how hard or smart you work in a given year?

If you're a self-employed craftworker who produces hammers, should your income be the same each year, without regard for the quality or quantity of hammers you produced that year, and without considering the world's need for the sorts of hammers you produced? How would you go about achieving that outcome?