Question about subq fluids cat

Hi , everyone i am really struggling with managing to give my cat his subq fluids ... and I figured instead of making it worse for him and me , I'll retry again tomorrow. I managed to go give him 1 of the 3 of 50 ml a day ... so I guess its something is that oke for 1 day and that I'll redo it tomorrow? Now another question can I save the fluids that's already in the syringe in there and reuse tomorrow? Or should I discard it and get new fluids in the syringe tomorrow? And a new buttfly needle too I imagine?