These teachings of the Ordinary Magisterium are referred to by then Cardinal Ratzinger, with particular wording, as the non-infallible teaching of the Magisterium and non-irreformable magisterial teaching, in the document issued by the Congregation for the Doctrine of the Faith called 'The Ecclesial Vocation of the Theologian,' n. 28 and 33. This wording demonstrates Cardinal Ratzinger's understanding that not all Magisterial teachings are infallible or irreformable.
In the same Address to the U.S. Bishops cited above, Pope John Paul II said: With respect to the non-infallible expressions of the authentic magisterium of the Church, these should be received with religious submission of mind and will. Clearly, the term religious submission of will and intellect refers to the ordinary non-infallible teachings of the Magisterium and is a different degree and type of assent than the divine and Catholic faith due to infallible teachings.
Therefore, the Magisterium can teach both infallibly and non-infallibly. Heresy is the denial or obstinate doubt of the infallible teachings and also of those ordinary teachings which are essential to salvation; heresy is a refusal to give the full assent of faith due to those teachings. The denial or doubt of non-infallible teachings in general might also be sinful and culpable, but the sin is not generally the sin of heresy and is a lesser matter, because the assent required is a lesser degree of assent.
The teachings of the Ordinary Universal Magisterium (i.e. the Universal Magisterium) are certainly infallible, but these are distinguished from the non-infallible, non-irreformable teachings of the Ordinary Magisterium themselves, whose number and extent cannot be trivial. Those who claim that nearly every teaching of the Ordinary Magisterium actually falls under the Universal Magisterium are in effect extending infallibility to the Ordinary Magisterium itself, because the teachings they claim to be infallible under the Universal Magisterium have not in fact been taught universally by the Church. Such persons also err grievously by reducing the kind and number of the teachings of the Ordinary Magisterium, so that no ordinary teachings are left of any significance.
This article from the link concludes with:
So, I wonder how many "faithful" Catholics can even know what teachings they are being given are, by their own estimation, fallible or infallible? I know when I was Catholic there was no room for doubts of anything I was taught and to question was deemed a sin. Why the need for such legalese for something, admittedly, was only actually used once???
The first thing we need to understand is that dogmas NEVER change, practices do. Doctrines may be revised is a very few specific ways:
1) Doctrines that are implicit in Tradition and Scripture become explicit or may be confirmed as dogma.
2) Doctrines that are explicit develop over time so as to be more fully understood. 3) Non-infallible doctrines can be corrected or changed; i.e.; Limbo was taught by many Bishops for time.
This is an ongoing debate btwn RCs.