It's important to note that while it is generally used in a loving and respectful way, it can sometimes be considered informal or even disrespectful depending on the context and the relationship between the speaker and the person being referred to.
Here are some ways you might see "mi vieja" used:
* "Voy a visitar a mi vieja." (I'm going to visit my mother/grandmother.)
* "Mi vieja me hizo mi platillo favorito." (My mother/grandmother made my favorite dish.)
* "Mi vieja es la mejor." (My mother/grandmother is the best.)
It's always best to use caution when using this term, especially if you are not a native speaker. If you're unsure, it's safer to use a more formal term like "mamá" or "abuela" instead.