Fodo. Sparky is ABSOLUTELY CORRECT. You have ventured into the world of the "Not so Nice" person. They will do everything they can to beat you out of your hard earned dollar. If you do service work for homeowners you will find that they will give you a check when you ask and it will never bounce. Doing small jobs (light fixtures, fans, timers etc.) for homeowners will get you a cash flow. THEY ALWAYS PAY.
When you work for Contractors or homeowners where you are doing remodel or new work you will not find that same luxury.
If you have a good paying contractor keep him all the rest get rid of. I know it will make your life better.
I used to have mixed emotions about getting a deposit before doing the work and actually thought along the lines of Tom. And that is why I am not in business any longer. Tom is correct if you're smart enough or have the luxury of starting a business with some capital. I should have talked to him in 1991.
You, like me do not have that luxury so get that deposit and get a permit. I'm not sure how it works in Ky but if they require a permit get one it will help your cause along with a contract.
A lot of commercial jobs require holding a retainer so make sure you know what it is so you can plan your expenses for it.
When I was in business I thought cash work was wonderful because I did not have to declare it but it is like being a waiter or bartender. By the next day you have spent it on some frivolous items. Now when your bills come due you have to scramble for the money.
Put all you money in the company checking account and draw a salary. You may already do this but if not do it.
I will give you one bit of advise someone gave me just after I went into business and I should have listened: "Everyone wants your money before you".
Avoid "Punch out" lists they will drowned you in them. Charge for extras - all extras. Write them down, get them signed by the important person, then do them, not before. Remember you are an Electrician you can work anywhere anytime. That is your best way to accomplish Sparkys' Rule #4. Don't let them intimidate you.
Long winded I know and I could go on and on but if I can help one person with this advise it is worth it.
Good Luck