I'd have some tough thinking to do. What business do I get into? What "life" things do I give up in order to have the time required to run a business on the side? How do I handle customer needs that come up while I am working my regular job? I'm not good at sales and marketing, so how do I manage getting help with those things? So far, I haven't been able to solve those problems.
Self-financed, no long term debt.
Except for my emergency fund and my retirement funds, I don't have ready cash. I'm not willing to empty either fund to risk it all starting a business. Unless I can find something I want to do that doesn't require much initial investment (and I haven't found anything yet), I'd have to get a loan.
Something in which you have a passionate interest, and really like. Because you are going to be doing a lot of it. If you do not like the work, you should not start a business, because then such a business becomes a job, and not a very good one.
What "life" things do I give up in order to have the time required to run a business on the side?
Whatever it takes. Sounds trite, but if you cannot invest money, then you have to invest time. Preferably both.
How do I handle customer needs that come up while I am working my regular job?
I did it nights weekends and holidays. I found that I was SO GLAD to have customer needs that it did not really feel like disagreeable work.
Since I was working and making a living when I started I did not need the business sales revenues, so plowed them all back into the business. Equipment, inventory, advertising. If you do it this way you do not have to touch your savings or retirement or ever need a loan, until such time that you expand enough to need to meet payrolls. By then, you have made it.
The most honest answer I have:
I think the biggest thing people will agree about is "You have to WANT it." If it is merely something that sounds like a nice idea, you will not make it go. It's hard work, lots of it. By the time my career ended I was working over a hundred hours a week. And I am glad I did. Because when the career ended, the lifeboat was almost ready. The first year was awful. The next one was bad, but bearable. The next one was nice. The next one was really good. This one is better.
If you think you hate taxes and health insurance costs now...haha. Just watch.