Many great performers have much to say about practicing slowly. Orchestral musicians especially have the habit of setting the metronome at a slow speed (maybe half tempo) and gradually increasing the tempo a notch at a time to eventually bring a difficult passage up to full speed. Since flawless accuracy is the goal, so many repetitions ultimately pay off.
One concern, though, is that if we don’t pay attention while practicing slowly, we really don’t improve very much. Great athletes practice complex plays or strategic movements in “slow motion” in order to analyze precisely where every part of the body must be in order to perfectly execute the maneuver. Just moving slowly isn’t enough–mindful technical analysis at a slow tempo is the goal.
So, practice a challenging passage slowly. Pay attention to every movement of your fingers. Notice where glitches occur, then back out and try again in order to “fix” the problem. If this passage is like the pattern a wide receiver will run to evade the defender and make a spectacular catch in the end zone, every footstep will be carefully mapped. The angle of the body, the position of the hands, and the gaze of the eyes all will be a part of the design.
On the bassoon, complex fingering patterns and movements combine for every interval. Become sensitive to how every accurate fingering feels so that you may be able to recognize errors. Choreograph the passage and learn where you need to focus your concentration. Where do you need to be looking? Make the most of your “slow motion” practice in order to perfect even the most difficult music.