Interior Plywood Thickness

I'm planning out the interior of the cabin and have a question about plywood thicknesses used.
I'll be using baltic birch ply. For areas like shelving, the headboard and "cabinetry" areas like that, is it best to use 3/4 inch ply (18mm-13 ply) or is 1/2 inch (12mm-9 ply) an okay choice.
The supplier also has a 5/8 inch ply (15 mm-11 ply).
I'm thinking about weight savings but also wondering if 3/4 is a bit hefty.
I'd be interested in people's thoughts on this.
thanks very much!!
John
I'll be using baltic birch ply. For areas like shelving, the headboard and "cabinetry" areas like that, is it best to use 3/4 inch ply (18mm-13 ply) or is 1/2 inch (12mm-9 ply) an okay choice.
The supplier also has a 5/8 inch ply (15 mm-11 ply).
I'm thinking about weight savings but also wondering if 3/4 is a bit hefty.
I'd be interested in people's thoughts on this.
thanks very much!!
John