swapping between sorting algorithms for small input size left over
People don't usually program their own sorting routines, and I would advise against it, unless you're implementing a non-comparison-based sort such as counting sort. Library sorting routines are optimized beyond what the casual programmer can achieve.

If you're interested in the best practices of the field, you'll have to look at library sorting routines. For example, python uses Timsort, which switches to insertion sort for small arrays. The GNU implementation of Quicksort also switches to insertion sort for small arrays. So it seems switching to insertion sort for small arrays is indeed advisable.