Ever had someone say they will do something and then not do it ? Have you even did the same? With the exception of the couple of occasions where not doing that you said may be warranted, the majority of the time it is doing a disservice to yourself and others.
Fulfill Your Obligations is the 15th precept in The Way to Happiness book. One is born with certain obligations and they tend to accumulate afterwards. The kid helping mom, the high school student getting a job and so on are all part of fulfilling your obligations.
One of the main way of not fulfilling it is in the area of incurred debt. One can help a person who finds himself in the dilemma of unpaid obligations and debt by simply going over with them all the obligations they have incurred and have not fulfilled and work out some way to fulfill them.
So do what you say you will and discourage yourself or anyone from incurring more obligtions than it is possible to repay.