How can I decide whether Quicksort or Mergesort is better for a given situation?

It is known that Quicksort and Mergesort are both efficient, fast sorting algorithms, although both of them have their different weaknesses.
Stability is one such aspect that is worth noting. When a data structure contains keys leading to the data within itself, an unstable sorting algorithm will switch around different keys containing the same data, which is undesirable as it breaks the order of the keys.
In Quicksort's case, it has the risk of being unstable, and thus it could mess up a data structure featuring keys with identical data attached to them. On the other hand, Mergesort has the advantage of being always stable.
Although Mergesort is typically just slightly slower than Quicksort in most cases, when we have a data structure that is sorted almost completely in order, or one that is sorted in reverse, we will observe that Quicksort's average time complexity becomes relatively bad, in contrast to Mergesort's which performs slightly better.
Differentiating between Quicksort and Mergesort and choosing which one would be more optimal to implement depends on each data structure and the information we know about it.