They are open minded for business they don't overspend their money.
They only buy what they need or what they could afford unlike most of us we would take a loan just to have what we want just to celebrate what we want.
They know how to control their money.
good words.
in other words, financial management is the most important thing if they want to become a successful businessman. many people who are just trying to learn business but they often forget important things like that. my personal opinion, controlling money is indeed very difficult especially when a desire is greater than its usefulness (I feel that I am not yet suitable in business).
One thing to note as well is that most of these self made millionaires did it over a long time. It doesn't happen overnight. There probably were a lot of disappointments and heartbreaks along the way. I'm not yet a millionaire but i think one way to go there would be to not be afraid of going for a long run. Small steps forward would one way or another get you to your goal. It may take years but look at those people at the top. They made it there because of their determination.