For the most practical setup, aim for your nightstand to sit between 5 and 10...

https://lilyluxemaids.com/the-golden-ratio-of-bedside-comfort-matching-your-mattress-to-a-60-63-cm-nightstand/

For the most practical setup, aim for your nightstand to sit between 5 and 10 centimetres below the top of your mattress. This keeps your water and phone within easy reach while you are in bed