Perform an update or install a package, things break. Usually Macports itself would partially or entirely stop working. Not the same way every time. After the first couple times I learned that attempts to fix it usually didn't entirely solve the problem and/or took too long, so I just started deleting the whole thing and starting over when things went wrong. At least re-installing packages doesn't require my full attention.

2012 may have been around when I stopped using it, can't recall for sure. Maybe it improved after I dropped it.