One of the themes in my overall development has been slow practice. It wasn't until my sophomore year in college that I really understood what it actually meant. I had begun to not only practice notes and rhythms at slow tempos, but I also started slowing the motions themselves down. This could be compared to Tai Chi as far as the idea of slow movements giving you a chance to pin point and fix any unnecessary tension or hesitation. I literally think about every aspect of my strokes and movements towards and away from notes or positions that my body finds itself in. As I speed things along, I try to maintain, as closely as possible, the feeling of ease and care that each stroke had when it was slow. This has done wonders for my overall playing and my awareness during performance.
My best friend, Sara Neilson, is a bassist and she once decided that she would try to play her long tone exercises as slow as 30bpms. Of course this is difficult because there has to be a certain amount of impulse to get the note going, and there has to be a certain amount of pressure and speed to the stroke to sustain it. I think she eventually was able to play a 56 second long tone....WIth 1 down bow! She of course saw great improvement in her playing overall. This attention to her basic stroke helped her fix more things in less time and that's exactly why I continue to do the same. We now play long tones together whenever we are in the same city. My favorite dance duo, Les Twins, also practice slowly and even perform in slow motion at times (which literally looks unreal). It's amazing to see their bodies, not emulating the perception of slow motion, but actually doing the movements slow! It was incredible.
So please, don't count out the importance of practicing slow. It gives you a chance to locate any mistakes you are prone to making, or even notice bad tendencies and habits during your performance. Take the time now so you don't have to relearn or unlearn anything. Literally, slow and steady will get you to where you want to go.