For a comfortable bedroom, your nightstand should sit between 55 and 70...

https://www.bookmark-belt.win/the-golden-rule-for-bedside-tables-is-comfort-aim-for-your-nightstand-to-sit

For a comfortable bedroom, your nightstand should sit between 55 and 70 centimetres high. The golden rule is to keep the tabletop about 5 to 10 centimetres below your mattress top