I am in the fifth year of my second business.
I do engineering and construction in Northern California.
A lot of things have changed since my first business; most of them cost more money. The main increases have come from the cost of insurances (general liability, workman's comp. etc), and employee salaries. If I can find a good employee, I need to pay them enough so that they can live. Also for some reason most employees think that I need to pay for their tools, truck, travel & gas!
Both of my businesses I was able to start our small and grow. I always put money back into my business to grow it, and try to keep my debt down. Depending on what type of business you are looking at will decide whether or not you can do that. You dont want to go into too much debt because it is YOUR BALLS on the line. And dont ever forget that, especially when you get a whiney, bitchy employee. If you get a cancer employee as I call them, get rid of them immediately! Dont hire friends or another employees spouse or cousin or whatever, causes too many problems when one of them turns out to be a cancer employee.
Anyway I dont know if I helped or if I am just ranting, but do make sure that you LOVE the type of work that you will be doing. You will be eating, sleeping & shitting your business, you have to. Dont get me wrong, I couldnt imagine doing anything else, but it is not for everyone.
Good luck, Eric.