A little note to myself: Whatever advice or samples that you give to a client is most often going to be exactly what they implement. In order to minimize your support costs, it should be very important to treat your sample projects with the same level of care as you would your main source tree.

Giving a client a well-factored sample, instead of something hacked up in an hour or so, will not only increase the likelihood of a successful implementation but also give the client a good feel for the overall internal quality of the product they have purchased.