I think you've hit on an important constraint that is almost never considered by the companies that offer estatements. Namely, why allow only one email address to receive the statement? If the companies that want me to convert to estatements would let me specify more than one email address to send the statement to, I would gladly use the option. As is, with just one email address, I will have to keep receiving the paper bill. Yes, I've been in paper mills, but I'm not concious stricken about using paper. Note to application architects, developers etc.: always allow for more than one email address for this type of application (billing, statements, etc.). Also, big pet peeve: let me specify a PO Box on address line 2. If you really need my physical address, I'll put it on address line 1. My local Post Office does not, for some reason, deliver to my physical address, so I get my mail at the Post Office (in fact, I use a gasoline powered car to go there). Not being able to plainly specify my PO Box on address line 2 leads to all sorts of artifice to trick the application into specifying something the Post Office will recognize as my PO Box number.

Sander, thanks for the reminder about your books. I've downloaded and read some of your earlier books, and the new ones will be useful. You have a good ability to explain and illustrate. Thanks also to your publisher for making these available.

If I copy-paste more than a few lines of code, based on an example I found on a web page (usually CP or StackOverflow), I put the complete URL to the page as a comment in the method header. That way, I can quickly go back to the original source and review the "documentation", such as it is.

If the amount of money at stake is worth pursuing, consider having a collection agency work for you (one of the reputable ones). I had to use an agency a number of years ago for software prodcuts that I sold. Several clients did not pay, when the agency got involved, I was able to recover about 75% of what was owed. This is probably more expeditious and less costly than hiring an attorney, who might be motivated to run up the hours. The agency gets a cut of the recovery, so their motivation is to move the process along. Also, a good agency is well versed in all of the legal angles, and can ramp up the pressure on the non-paying client in a way that complies with all applicable laws. The agency that I used had a multi-step process, eventually leading to legal action against the non-paying client (the legal action was performed by their attorney, and was included in their cut). This removes a lot of the emotional pressure on you: you no longer need to be thinking vengeful thoughts and contemplating actions that will get you into a much deeper problem than you want to be involved with. If the software that you developed is important to your client, will they not need to return to you at sometime in the future for fixes/enhancements? Let the collector do the work, and allow the situation to quiesce. When the client is ready to work with you again, you can start with a deposit to cover the amount lost to the collector and cover the anticipated amount that you will bill.