The golden rule for bedside tables is comfort and accessibility. Aim for a...

https://www.toro-bookmarks.win/as-a-rule-of-thumb-keep-your-nightstand-level-with-your-mattress-or-just-5-10

The golden rule for bedside tables is comfort and accessibility. Aim for a height that sits between 5 and 10 centimetres below the top of your mattress. Most standard beds work best with tables in the 55 to 70 centimetre range