I've always found it curious why people train in strict rep ranges as if there's some magical number.
It's not difficult to incorporate the entire spectrum in a single workout and reap the full benefits of varied rep ranges.
I use the full 5 to 15 rep (sometimes 20) range on every workout. I will often end up with 4, 6, 7, 9, 11, 13, and 14 reps on a set when I didn't quite reach my goal, or my goal was too light.
In my workouts I have certain exercises where I'll max out at 5 reps (bench press, squats, presses, inclines etc), but then come back to a lighter weight and bang out 10 - 12 reps for 1 or 2 sets. On other exercises I'll use higher reps all the time.