Mr. Jefferson often advised folks on issues of personal conduct, and he developed a list of axioms for personal behavior. Some were his own creation; others derived from earlier sources.
A Decalogue of Canons for Observation in Practical Life
1. Never put off to tomorrow what you can do to-day.
2. Never trouble another with what you can do yourself.
3. Never spend your money before you have it.
4. Never buy a thing you do not want, because it is cheap, it will be dear to you.
5. Take care of your cents: Dollars will take care of themselves.
6. Pride costs us more than hunger, thirst and cold.
7. We never repent of having eat too little.
8. Nothing is troublesome that one does willingly.
9. How much pain have cost us the evils which have never happened.
10. Take things always by their smooth handle.
11. Think as you please, and so let others, and you will have no disputes.
12. When angry, count 10. before you speak; if very angry, 100.
Later in life, Jefferson shortened his list to ten by omitting #5 and #11. I don't know if he thought they were redundant (likely for #5) or he changed his mind (unlikely).
So, here they are - the final 10 rules to live by:
1. Never put off tomorrow what you can do today.
2. Never trouble another for what you can do yourself.
3. Never spend your money before you have earned it.
4. Never buy what you don’t want because it is cheap.
5. Pride costs more than hunger, thirst and cold.
6. We seldom repent of having eaten too little.
7. Nothing is troublesome that we do willingly.
8. How much pain the evils have cost us that never happened.
9. Take things always by the smooth handle.
10. When angry, count ten before you speak, if very angry, count a hundred.
Such a wise man. My admiration continues.