We all made them. We promised to be friends forever, to be godparents to our friends future children, to be in each others weddings. Once upon a time promises were easy to make. In the adult world however they are often hard to keep and sometimes you have to wonder if you are really bound by a promise you made 10 or 20 years ago.
The answer is generally no. As adults we all know that things don't always work out the way we envisioned them. However if you are still friends with the person over a decade later even if you can't keep your promise, the friendship is obviously important enough that you at least owe an explanation.
Lets say Jen and Jane have a pact to name their children after each other using middle names. 10 years after graduation Jane has the first baby. Rather that using Daniel as a first or middle name (Danielle was Jen's middle name) she names the baby John Alexander. Jen's feelings are understandably hurt, a promise was broken. However if Jane takes the time to explain John and Alexander were her husbands twin brother who died in a car accident as children it would save a lot of hurt feelings.
If on the other hand Jane just names the child and figures Jen won't care she is probably sadly mistaken.