How big is your DC's water bottle, 500ml or 350ml?

[Octavia09]

My DS has 700ml water bottle and I am thinking of buying him a smaller one, maybe 350ml. Should be enough as he does not drink even half of the water anyway.

My 3 have 500ml bottles, but I only tend to half fill them as they walk to school and full bottles are heavy to carry especially when they have swimming kits, hockey sticks, homework folders etc to carry as well.

There is a water cooler in school that they can use to refill them if they drink all of the water that is in them.

My DS has a bookbag, a PE bag and a little backpack with his box for banana and the water bottle. There is not really that much space for everything to put on the hook and I do not want to stick everything in the bookbag. So I am thinking of buying a smaller water bottle and put it in the baby water bottle bag. There would be some place on the top of the bottle for an apple.