In Oregon if/when someone writes a bad check they are liable for 3X the amount. I have a close friend in the information business who handles all of my collections for me. I'll give a brief description below but basically I almost get excited when someone passes me a bad check or tries to skip out on an invoice.

For a bad check:

You have to find an address... this can be done with a basic DMV search which is very cheap. The address they provide at the time of the inspection, the license number of their car, etc can be enough. Once you find them it's a matter of drawing up small claims court papers and having them served. If/when they fail to show you must follow through and file a judgement against them but you will eventually get your money. Unless they die or totally drop off the face of the earth. Once you get the judgement you can attache it to their credit report and/or any property they own so they have to pay you before the get any other credit or sell their property. Granted, it's a bit of a hassle to go through but once you learn about it, it's not too bad.

For 'no pays' on an invoice -

Basically the same course of action. I have really good luck with certified 10-day demand letter (forgot to mention this is good for the bad check too). This is an important step to collect all the fees you incur while chasing them down. In the letter you must basically state the facts; You did X job for X amount of money and you will pursue the matter in small claims court by X date if you do not receive X amount of money. I enclose a copy of the contract with their signature which usually does the trick. I have a mid-sized company and have to go down this road about 10 times a year. I usually have 1 or 2 that don't pay after the demand letter. They never show up for court so I get a judgement and just wait for them to call. Usually, it's from a car dealership when they need some credit. I stick to them for all the fees from minute one (DMV search to find them, fee to serve them, interest, etc, etc)

It's really not too complicated but you have to learn how to do some things yourself. A couple calls to an information company can give you lots of answers. Actually, this stuff can usually be done from anywhere in the country so you don't even need someone local. One last caviat (Sorry, it's a home inspector thing) .... every state has different rules, laws, etc about information and how easy (which translates into $$) it is to find people.... I may have it good here in Oregon, I don't really know. But, like I mentioned I almost get excited when someone doesn't pay me