If you have several years successfully managing the kind of business you want to start, you are more likely to succeed than a person without similar successful business experience. If you don't have all the business skills you need, and very few business people have them all, you may need to train yourself on the missing elements or hire someone to do those tasks requiring skills you don't have. An example is the business person who hires an accountant to do the business taxes. Even though they are hired part time by the business, the expense may be far better than trying to learn about business taxes. Likewise, consulting an attorney on developing a business partnership agreement may be the best money you ever spent if the partnership goes sour.
People go into business for different reasons.
These are non-monetary objectives, that is, they aren't easy to put a dollar figure on. Other objectives are definitely monetary. You, and those dependent on you, need money to stay alive. Unless you expect to lower your standard of living, you will need to get from your business enough money to buy food, clothes, shelter, transportation, insurance, doctor services, taxes, etc. Most people have an idea of what business they want to go into.