For a comfortable bedroom, your nightstand should sit level with the top of...

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

For a comfortable bedroom, your nightstand should sit level with the top of your mattress or up to 10cm lower. Reaching for a glass of water is much easier when you aren't straining upwards