why is it important to align the cuvet in the sample holder the same way each time? cuvets must be aligned in the sample holder the same way each time because only two sides are transparent, so if it is placed incorrectly in the holder, then it will block the light and lead to an incorrect absorbance. cuvets must be aligned in the sample holder the same way each time in order to minimize any effect that imperfections in the glass will have on your results. both of the above are correct.