Shed - recommended shelf height

Would anyone share their opinion on the following? I'm having trouble deciding the proper height for the bottom storage shelf in a shed. Also, how much space should I leave between the 1st and second shelf.

I'm finishing up a shed and now I'm left with installing shelfs. I've decided to install sets of 2 16" deep shelfs on two of the walls which span across the entire wall lenght.

Using up half of the third wall (beind divided by a window) I'll be installing sets of 2 24" deep shelfs.

I usually use the height of the tallest object to be stored on or below shelfs to get an idea of these measures. That is easy inside the house, measure books/boxes. But wans't sure about the shed.

Thank you for any comments/suggestions.

I would place the 1st shelf 18" - 24" off the floor to allow for all those damn buckets of rock salt in the winter.