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

https://www.adirs-bookmarks.win/for-a-comfortable-reach-your-nightstand-should-sit-level-with-the-top-of-your

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